Journal of Bioscience and Bioengineering (JBB) 新着論文

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  • Gas chromatography coupled with mass spectrometry-based metabolomics for the classification of tempe from different regions and production processes in Indonesia

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Adinda Darwati Kadar, Pingkan Aditiawati, Made Astawan, Sastia Prama Putri, Eiichiro Fukusaki

    Tempe, a fermented soybean originally from Indonesia, is an excellent protein source with high nutritional quality. Differences in the production process and unique fermentation condition in different regions result in varieties of tempe. Despite its high cultural and economic values, there are very few studies on the characterization of tempe based on the differences of production process and geographical origin. Metabolomics is a powerful tool assessing food quality, food safety, and determination of origin and varietal differences. In this study, metabolomics is applied for the study of Indonesian tempe obtained from various regions and different production processes. Seventeen samples were collected from 6 different cities in Java Island, which were produced by local tempe crafters (traditional), semi-modern industry and modern industry. Untargeted metabolomics by gas chromatography coupled with mass spectrometry (GC/MS) was implemented to discriminate various kinds of tempe and identify metabolites that are associated with these differences. Results showed that tempe produced in different places clustered together according to the cities and their production category. Sugars and amino acids groups were found to be primary compounds that contributed to this result. This is the first report that address the metabolic differences between different varieties of tempe from different regions and production processes. The knowledge from this study is important for future development of tempe production.

  • Epipremnum aureum and Dracaena braunii as indoor plants for enhanced bio-electricity generation in a plant microbial fuel cell with electrochemically modified carbon fiber brush anode

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Pranab Jyoti Sarma, Kaustubha Mohanty

    In this study, two different unexploited indoor plants, Epipremnum aureum and Dracaena braunii were used to produce clean and sustainable bio-electricity in a plant microbial fuel cell (PMFC). Acid modified carbon fiber brush electrodes as well as bare electrodes were used in both the PMFCs. A bentonite based clay membrane was successfully integrated in the PMFCs. Maximum performance of E. aureum was 620 mV which was 188 mV higher potential than D. braunii. The bio-electricity generation using modified electrode was 154 mV higher than the bare carbon fiber, probably due to the effective bacterial attachment to the carbon fiber owing to hydrogen bonding. Maximum power output of 15.38 mW/m2 was obtained by E. aureum with an internal resistance of 200 Ω. Higher biomass yield was also obtained in case of E. aureum during 60 days of experiment, which may correlate with the higher bio-electricity generation than D. braunii.

    Graphical abstract

    Graphical abstract for this article

  • 3D-printed scaffolds with calcified layer for osteochondral tissue engineering

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Zhengyu Li, Shuaijun Jia, Zhuo Xiong, Qianfa Long, Shaorong Yan, Fu Hao, Jian Liu, Zhi Yuan

    Treating full-layer injury of bone and cartilage is currently a significant challenge in orthopedic trauma repair. Joint damage typically includes chondral defects, and the underlying subchondral defect sites are difficult to repair. Tissue engineering technology could potentially be used to treat such injuries; however, results to date been unsatisfactory. The aim of this study was to design a multilayer composite scaffold containing cartilage, bone, and calcified layers to simulate physiological full-thickness bone-cartilage structure. The cartilage layer was created using an improved temperature-gradient thermally induced crystallization technology. The bone and calcified layers were synthesized using 3D printing technology. We examined the scaffold by using scanning electron microscope (SEM), X-ray diffraction (XRD), fluorescence staining, and micro computed tomography (Micro-CT), and observed clearly oriented structures in the cartilage layer, overlapping structures in the bone scaffold, and a compressed calcified layer. Biomechanical performance testing showed that the scaffolds were significantly stronger than scaffolds without a calcified layer (traditional scaffolds) in maximum tensile strength and maximum shear strength (P < 0.05). After inoculating cells onto the scaffolds, we observed similar cell adherence and proliferation to that observed in traditional scaffolds, likely because of the high porosity of the whole scaffold. Our scaffolds could be used in bone and cartilage full-thickness injury repair methods, as well as applications in the field of tissue engineering.

  • High cell density suppresses BMP4-induced differentiation of human pluripotent stem cells to produce macroscopic spatial patterning in a unidirectional perfusion culture chamber

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Shota Tashiro, Minh Nguyen Tuyet Le, Yuta Kusama, Eri Nakatani, Mika Suga, Miho K. Furue, Taku Satoh, Shinji Sugiura, Toshiyuki Kanamori, Kiyoshi Ohnuma

    Spatial pattern formation is a critical step in embryogenesis. Bone morphogenetic protein 4 (BMP4) and its inhibitors are major factors for the formation of spatial patterns during embryogenesis. However, spatial patterning of the human embryo is unclear because of ethical issues and isotropic culture environments resulting from conventional culture dishes. Here, we utilized human pluripotent stem cells (hiPSCs) and a simple anisotropic (unidirectional perfusion) culture chamber, which creates unidirectional conditions, to measure the cell community effect. The influence of cell density on BMP4-induced differentiation was explored during static culture using a conventional culture dish. Immunostaining of the early differentiation marker SSEA-1 and the mesendoderm marker BRACHYURY revealed that high cell density suppressed differentiation, with small clusters of differentiated and undifferentiated cells formed. Addition of five-fold higher concentration of BMP4 showed similar results, suggesting that suppression was not caused by depletion of BMP4 but rather by high cell density. Quantitative RT-PCR array analysis showed that BMP4 induced multi-lineage differentiation, which was also suppressed under high-density conditions. We fabricated an elongated perfusion culture chamber, in which proteins were transported unidirectionally, and hiPSCs were cultured with BMP4. At low density, the expression was the same throughout the chamber. However, at high density, SSEA-1 and BRACHYURY were expressed only in upstream cells, suggesting that some autocrine/paracrine factors inhibited the action of BMP4 in downstream cells to form the spatial pattern. Human iPSCs cultured in a perfusion culture chamber might be useful for studying in vitro macroscopic pattern formation in human embryogenesis.

  • Xylosylation of proteins by expression of human xylosyltransferase 2 in plants

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Kouki Matsuo, Go Atsumi

    Through the years, the post-translational modification of plant-made recombinant proteins has been a considerable problem. Protein glycosylation is arguably the most important post-translational modification; thus, for the humanization of protein glycosylation in plants, the introduction, repression, and knockout of many glycosylation-related genes has been carried out. In addition, plants lack mammalian-type protein O-glycosylation pathways; thus, for the synthesis of mammalian O-glycans in plants, the construction of these pathways is necessary. In this study, we successfully xylosylated the recombinant human proteoglycan core protein, serglycin, by transient expression of human xylosyltransferase 2 in Nicotiana benthamiana plants. When human serglycin was co-expressed with human xylosyltransferase 2 in plants, multiple serine residues of eight xylosylation candidates were xylosylated. From the results of carbohydrate assays for total soluble proteins, some endogenous plant proteins also appeared to be xylosylated, likely through the actions of xylosyltransferase 2. The xylosylation of core proteins is the initial step of the glycosaminoglycan part of the synthesis of proteoglycans. In the future, these novel findings may lead to whole mammalian proteoglycan synthesis in plants.

  • Real-time monitoring of pH-dependent intracellular trafficking of ovarian cancer G protein-coupled receptor 1 in living leukocytes

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Modong Tan, Satoshi Yamaguchi, Motonao Nakamura, Teruyuki Nagamune

    G-protein coupled receptors (GPCRs) are involved in many diseases and important biological phenomena; elucidating the mechanisms underlying regulation of their signal transduction potentially provides both novel targets for drug discovery and insight into living systems. A proton-sensing GPCR, ovarian cancer G protein-coupled receptor 1 (OGR1), has been reported to be related to acidosis and diseases that cause tissue acidification, but the mechanism of proton-induced activation of OGR1-mediated signal transduction in acidic conditions remains unclear. Here, pH-dependent intracellular trafficking of OGR1 was visualized in living leukocytes by a real-time fluorescence microscopic method based on sortase A-mediated pulse labeling of OGR1. OGR1 labeled on the cell surface with a small fluorescent dye was clearly observed to remain in the plasma membrane during incubation in mildly acidic medium (pH 6.6) and to be internalized to the intracellular compartments on changing the medium to slightly basic pH (7.7). Quantitative single-cell image analysis showed that most of the internalized OGR1s were then recycled to the plasma membrane for signal transduction if the extracellular pH was returned to the mildly acidic state. However, in a minor population of cells (40%), the internalized OGR1s were retained in endosomes or transported to lysosomes and degraded, leading to low efficiency of their recycling to the plasma membrane. Thus, the present live-cell monitoring strongly suggests that the signal transduction activity of OGR1 is regulated by pH-dependent internalization and recycling to the plasma membrane.

  • Characterization of the 3-methyl-4-nitrophenol degradation pathway and genes of Pseudomonas sp. strain TSN1

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Masahiro Takeo, Kenta Yamamoto, Masashi Sonoyama, Kana Miyanaga, Nana Kanbara, Koichi Honda, Dai-ichiro Kato, Seiji Negoro

    3-Methyl-4-nitrophenol (3M4NP) is formed in soil as a hydrolysis product of fenitrothion, one of the major organophosphorus pesticides. A Pseudomonas strain was isolated as a 3M4NP degrader from a crop soil and designated TSN1. This strain utilized 3M4NP as a sole carbon and energy source. To elucidate the biodegradation pathway, we performed transposon mutagenesis with pCro2a (mini-Tn5495) and obtained three mutants accumulating a dark pink compound(s) from 3M4NP. Rescue cloning and sequence analysis revealed that in all mutants, the transposon disrupted an identical aromatic compound meta-cleaving dioxygenase gene, and a monooxygenase gene was located just downstream of the dioxygenase gene. These two genes were designated mnpC and mnpB, respectively. The gene products showed high identity with the methylhydroquinone (MHQ) monooxygenase (58%) and the 3-methylcatechol 2,3-dioxygenase (54%) of a different 3M4NP degrader Burkholderia sp. NF100. The transposon mutants converted 3M4NP or MHQ into two identical metabolites, one of which was identified as 2-hydroxy-5-methyl-1,4-benzoquinone (2H5MBQ) by GC/MS analysis. Furthermore, two additional genes (named mnpA1 and mnpA2), almost identical to the p-nitrophenol monooxygenase and the p-benzoquinone reductase genes of Pseudomonas sp. WBC-3, were isolated from the total DNA of strain TSN1. Disruption of mnpA1 resulted in the complete loss of the 3M4NP degradation activity, demonstrating that mnpA1 encodes the initial monooxygenase for 3M4NP degradation. The purified mnpA2 gene product could efficiently reduce methyl p-benzoquinone (MBQ) into MHQ. These results suggest that strain TSN1 degrades 3M4NP via MBQ, MHQ, and 2H5MBQ in combination with mnpA1A2 and mnpCB, existing at different loci on the genome.

  • Rice straw pretreatment using deep eutectic solvents with different constituents molar ratios: Biomass fractionation, polysaccharides enzymatic digestion and solvent reuse

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Ao-Lin Li, Xue-Dan Hou, Kai-Peng Lin, Xuan Zhang, Ming-Hui Fu

    Lignocellulosic biomass pretreatment with deep eutectic solvents (DESs) is a promising and challenging process for production of biofuels and valuable platform chemicals. In this work, rice straw was mainly fractionated into carbohydrate-rich materials (CRMs) and lignin-rich materials (LRMs) by 90% lactic acid/choline chloride (LC)-water solution with different molar ratio of hydrogen bond donor (HBD, lactic acid) and hydrogen bond acceptor (HBA, choline chloride). It was found that high HBD/HBA molar ratio of DESs was favorable for achieving CRMs and LRMs with high purity, and both HBD and HBA were responsible for effective biomass fractionation possibly due to their synergistic effect on highly efficient breakage of the linkage between hemicellulose and lignin and thus lignin extraction. About 30%–35% of lignin in native rice straw was fractionated as LRMs, and exceeding 70% of xylan were removed and fractionated into the liquid stream as forms of xylose, furfural and humins after pretreatment using aqueous LC (3:1, 5:1) solution. Consequently, polysaccharides enzymatic hydrolysis of the CRMs were significantly enhanced. Moreover, all the DESs could be recovered with high yields of around 90%, and 69% of the LC (3:1) was recovered after 5 cycles reuse at 90 °C. Besides, the recycled DES maintained a good pretreatment ability, and glucose yields of 60–70% were achieved in the enzymatic hydrolysis of CRMs obtained in each cycle. The facile process established in present work is promising for large scale production of fermentable sugars and other chemicals.

  • Novel heterotrophic nitrogen removal and assimilation characteristic of the newly isolated bacterium Pseudomonas stutzeri AD-1

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Hui Qing, Oscar Omondi Donde, Cuicui Tian, Chunbo Wang, Xingqiang Wu, Shanshan Feng, Yao Liu, Bangding Xiao

    AD-1, an aerobic denitrifier, was isolated from activated sludge and identified as Pseudomonas stutzeri. AD-1 completely removed NO3 or NO2 and removed 99.5% of NH4+ during individual culturing in a broth medium with an initial nitrogen concentration of approximately 50 mg L−1. Results showed that larger amounts of nitrogen were removed through assimilation by the bacteria. And when NH4+ was used as the sole nitrogen source in the culture medium, neither NO2 nor NO3 was detected, thus indicating that AD-1 may not be a heterotrophic nitrifier. Only trace amount of N2O was detected during the denitrification process. Single factor experiments indicated that the optimal culture conditions for AD-1 were: a carbon-nitrogen ratio (C/N) of 15, a temperature of 25°C and sodium succinate or glucose as a carbon source. In conclusion, due to the ability of AD-1 to utilize nitrogen of different forms with high efficiencies for its growth while producing only trace emissions of N2O, the bacterium had outstanding potential to use in the bioremediation of high-nitrogen-containing wastewaters. Meanwhile, it may also be a proper candidate for biotreatment of high concentration organic wastewater.

  • Simulation of Pilsner-type beer aroma using 76 odor-active compounds

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Toru Kishimoto, Shigekuni Noba, Nana Yako, Minoru Kobayashi, Tetsuya Watanabe

    Gas chromatography-olfactometry (GC-O) analyses of the aroma components extracted from Pilsner-type beer were performed. The concentrations of all 76 components, that were identified after the GC-O analyses, were accurately quantitated. The aroma compounds were then used in the following aroma simulation experiments, with ethanol and water as matrices. The odorants with higher odor intensity in GC-O analysis and odor activity values (OAVs) were selected first, and the selected 25 odorants were used in an aroma simulation experiment. The results of sensory analysis showed that the simulation model using 25 odorants exhibited unbalanced characteristics and lacked the malty/cereal, estery characteristics, the total amount of aroma, and the similarity compared to the reference Pilsner-type beer. Addition of the 24 odorants, which were identified through the fractionations of whole aroma extract of beer and expected to complement the malty/cereal characteristic, could not improve the aroma quality of the simulation model. The aroma simulation experiments using 76 odorants indicated that the synergistic contributions of the multiple odorants, with no independent contribution to the overall characteristics (including sub-threshold components) and with no reminiscence of beer aroma, were necessary for the construction of beer aroma.

  • Deciphering synergistic characteristics of redox mediators-stimulated echinenone production of Gordonia terrae TWIH01

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Bin Xu, Bor-Yann Chen, Kuan-Chieh Huang, Qing-Jiang Sun, John Chi-Wei Lan

    This first-attempt study tended to decipher synergistic interactions of model redox mediators (RMs) to echinenone production for electrochemically-steered fermentation (ESF). The findings indicated that supplement of RMs could significantly stimulate the production performance of fermentation (e.g., 36% for 4-aminophenol) which was parallel with stimulation of bioelectricity generation in microbial fuel cells (MFCs) as prior studies mentioned. Although redox mediators could usually enhance electron transport extracellular compartment, the mechanisms of bioelectricity generation in MFCs and echinenone production in ESF were very likely functioned in the extracellular and the intracellular compartment, respectively. In MFCs, electron transfer towards biofilm anode for bioelectricity generation must be taken place. However, for ESF echinenone accumulation was very likely occurred in the intracellular compartment, thus electron transfer was predominantly implemented in the intracellular, not the extracellular compartment.

    Graphical abstract

    Graphical abstract for this article

  • Expression of Saccharomyces cerevisiae cDNAs to enhance the growth of non-ethanol-producing S. cerevisiae strains lacking pyruvate decarboxylases

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Yuki Narazaki, Yuta Nomura, Keisuke Morita, Hiroshi Shimizu, Fumio Matsuda

    Metabolic engineering of Saccharomyces cerevisiae often requires a restriction on the ethanol biosynthesis pathway. The non-ethanol-producing strains, however, are slow growers. In this study, a cDNA library constructed from S. cerevisiae was used to improve the slow growth of non-ethanol-producing S. cerevisiae strains lacking all pyruvate decarboxylase enzymes (Pdc, YSM021). Among the obtained 120 constructs expressing cDNAs, 34 transformants showed a stable phenotype with quicker growth. Sequence analysis showed that the open reading frames of PDC1, DUG1 (Cys–Gly metallo-di-peptidase in the glutathione degradation pathway), and TEF1 (translational elongation factor EF-1 alpha) genes were inserted into the plasmids of 32, 1, and 1 engineered strains, respectively. DUG1 function was confirmed by the construction of YSM021 pGK416-DUG1 strain because the specific growth rate of YSM021 pGK416-DUG1 (0.032 ± 0.0005 h−1) was significantly higher than that of the control strains (0.029 ± 0.0008 h−1). This suggested that cysteine supplied from glutathione was probably used for cell growth and for construction of Fe-S clusters. The results showed that the overexpression of cDNAs is a promising approach to engineer S. cerevisiae metabolism.

  • Purification and characterization of alginate lyase from Sphingomonas sp. ZH0

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Manman He, Min Guo, Xu Zhang, Keke Chen, Jinping Yan, Chagan Irbis

    Alginate lyases degrade alginate in a beta-elimination reaction to produce oligosaccharides. Thus, alginate lyases are widely used in the food/pharmaceutical industries and are commercially valuable. In this study, four alginate lyase encoding genes were successfully cloned from Sphingomonas sp. ZH0. The expression systems of these alginate lyases were then constructed in Escherichia coli cells. The recombinant ZH0-I, ZH0-II, ZH0-III and ZH0-IV were purified from E. coli cells and were confirmed to be monomeric enzymes with molecular weights of approximately 91, 52, 67, and 113 kDa, respectively. The conditions for enzymes to have the highest specific lyase activities were 53.2 U/mg, 42 °C, pH 7.0 for ZH0-I, 103.9 U/mg, 47 °C, pH 6.5 for ZH0-II, 13.7 U/mg, 52 °C, pH 7.5 for ZH0-III, and 12.3 U/mg, 37 °C, pH 7.0 for ZH0-IV, respectively. These recombinant enzymes were stable over a pH range. Moreover, the enzymes were active in the absence of salt ions, and their activities were substantially reduced by the addition of HgCl2. ZH0-I, ZH0-II and ZH0-III belong to endotype alginate lyases, while ZH0-IV is an exotype alginate lyase. All types could degrade both poly-β-d-mannuronate and poly-α-l-guluronate blocks, yielding alginate oligosaccharides as the main product. The Km and Vmax values were 0.51 mg/ml and 56.18 U/ml for ZH0-I, 0.47 mg/ml and 27.5 U/ml for ZH0-II, 0.55 mg/ml and 60.24 U/ml for ZH0-III, and 0.41 mg/ml and 5.53 U/ml for ZH0-IV, respectively. These features indicate that these alginate lyases are promising candidates for producing antioxidants from alginates in industrial applications.

  • Daidzein reductase of Eggerthella sp. YY7918, its octameric subunit structure containing FMN/FAD/4Fe-4S, and its enantioselective production of R-dihydroisoflavones

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Yuika Kawada, Tomoko Goshima, Rie Sawamura, Shin-ichiro Yokoyama, Emiko Yanase, Toshio Niwa, Akio Ebihara, Mizuho Inagaki, Keiichi Yamaguchi, Kazuo Kuwata, Yuta Kato, Osamu Sakurada, Tohru Suzuki

    S-Equol is a metabolite of daidzein, a type of soy isoflavone, and three reductases are involved in the conversion of daidzein by specific intestinal bacteria. S-Equol is thought to prevent hormone-dependent diseases. We previously identified the equol producing gene cluster (eqlABC) of Eggerthella sp. YY7918. Daidzein reductase (DZNR), encoded by eqlA, catalyzes the reduction of daidzein to dihydrodaidzein (the first step of equol synthesis), which was confirmed using a recombinant enzyme produced in Escherichia coli. Here, we purified recombinant DZNR to homogeneity and analyzed its enzymological properties. DZNR contained FMN, FAD, and one 4Fe-4S cluster per 70-kDa subunit as enzymatic cofactors. DZNR reduced the CC bond between the C-2 and C-3 positions of daidzein, genistein, glycitein, and formononetin in the presence of NADPH. R-Dihydrodaidzein and R-dihydrogenistein were highly stereo-selectively produced from daidzein and genistein. The Km and kcat for daidzein were 11.9 μM and 6.7 s−1, and these values for genistein were 74.1 μM and 28.3 s−1, respectively. This enzyme showed similar kinetic parameters and wide substrate specificity for isoflavone molecules. Thus, this enzyme appears to be an isoflavone reductase. Gel filtration chromatography and chemical cross-linking analysis of the active form of DZNR suggested that the enzyme consists of an octameric subunit structure. We confirmed this by small-angle X-ray scattering and transmission electron microscopy at a magnification of ×200,000. DZNR formed a globular four-petal cloverleaf structure with a central vertical hole. The maximum particle size was 173 Å.

  • Active site pocket of Streptomycesd-stereospecific amidohydrolase has functional roles in aminolysis activity

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Yasmeen Yousif Ahmed Elyas, Kazusa Miyatani, Tomohiro Bito, Misugi Uraji, Tadashi Hatanaka, Katsuhiko Shimizu, Jiro Arima

    d-Stereospecific amidohydrolase from Streptomyces sp. 82F2 (DAH) recognizes d-amino acyl ester derivatives as substrates and catalyzes hydrolysis and aminolysis to yield d-amino acids and d-amino acyl peptides or amide derivatives, respectively. Crystallographic analysis has revealed that DAH possesses a large cavity with a small pocket at the bottom. Because the pocket is close to the catalytic center and is thought to interact with substrates, we examined the function of the eight residues that form the pocket in terms of substrate recognition and aminolysis via mutational analysis. Formation of the acyl-enzyme intermediate and catalysis of aminolysis by DAH were changed by substitutions of selected residues with Ala. In particular, I338A DAH exhibited a significant increase in the condensation product of Ac-d-Phe methyl ester and 1,8-diaminooctane (Ac-d-Phe-1,8-diaminooctane) compared with the wild-type DAH. A similar effect was observed by the mutation of Ile338 to Gly and Ser. The pocket shapes and local flexibility of the mutants I338G, I338A, and I338S are thought to resemble each other. Thus, changes in the shape and local flexibility of the pocket of DAH by mutation presumably alter substrate recognition for aminolysis.

  • Development of polyhydroxyalkanoates production from waste feedstocks and applications

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Harshini Pakalapati, Chih-Kai Chang, Pau Loke Show, Senthil Kumar Arumugasamy, John Chi-Wei Lan

    Polyhydroxyalkanoates (PHA) are naturally occurring biopolymers, obtained from microorganisms. Properties like biodegradability and biocompatibility make PHA a part of today's commercial polymer industry. However, the production cost of PHA has been a great barrier to extend its application to large scale production. Substrates and usage of pure cultures constitute the main reason for its high production cost. On the other hand, rapid industrialization i.e., industrial sectors such as sugar, pulp and paper, fruit and food processing, dairies, slaughterhouses, and poultries, has resulted in the generation of the huge quantity of wastes. Consequently, becoming large source of environmental pollution and health hazard. This review emphasizes on the usage of various waste feedstocks obtained from industrial and agricultural industries as an alternate substrate for PHA production. As these waste materials are rich in organic material and also microbes, they can be the good starting material for PHA production. Additionally, advantages and economic importance of mixed cultures and also PHA applications are discussed. Future prospects and challenges in PHA production from waste feedstocks are also highlighted.

  • Recovery of biotechnological products using aqueous two phase systems

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Win Nee Phong, Pau Loke Show, Yin Hui Chow, Tau Chuan Ling

    Aqueous two-phase system (ATPS) has been suggested as a promising separation tool in the biotechnological industry. This liquid-liquid extraction technique represents an interesting advance in downstream processing due to several advantages such as simplicity, rapid separation, efficiency, economy, flexibility and biocompatibility. Up to date, a range of biotechnological products have been successfully recovered from different sources with high yield using ATPS-based strategy. In view of the important potential contribution of the ATPS in downstream processing, this review article aims to provide latest information about the application of ATPS in the recovery of various biotechnological products in the past 7 years (2010–2017). Apart from that, the challenges as well as the possible future work and outlook of the ATPS-based recovery method have also been presented in this review article.

  • Rapid multiplex nucleic acid amplification test developed using paper chromatography chip and azobenzene-modified oligonucleotides

    Publication date: September 2018

    Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 3

    Author(s): Sotaro Sano, Shigehiko Miyamoto, Seiji Kawamoto

    Although nucleic acid amplification test (NAT) is widely used for pathogen detection, rapid NAT systems that do not require special and expensive instruments must be developed in order to enable point of care (POC)-NATs, which contribute to early initiation of treatment. As a POC-NAT system, Kaneka DNA chromatography chip (KDCC), developed using DNA tag-bound primer through modified substance, was shown to be suitable for POC testing, due to the rapid detection time, simple procedures, and low manufacturing costs. However, owing to some modifications in primer, the detection performance and amplification speed were shown to be reduced when using KDCC, counteracting the increased speed of detection. To solve these issues and improve the speed of this NAT system, we investigated a better modification substance for KDCC. Here, azobenzene-modified primers were shown to have the highest amplification speed and detection performance in KDCC, of all modifications tested in this study, showing 10–100-fold lower detection limit but maintaining the same reaction time. Additionally, rapid herpes simplex virus detection system with azobenzene modified primers was developed. We believed that this breakthrough will contribute toward enabling greater utilization of POC-NATs for medical care, especially in developing countries and clinics.

  • Comparison of biofunctional activity of Asparagus cochinchinensis (Lour.) Merr. Extract before and after fermentation with Aspergillus oryzae

    Publication date: Available online 8 August 2018

    Source: Journal of Bioscience and Bioengineering

    Author(s): Guey-Horng Wang, Yi-Min Lin, Jong-Tar Kuo, Chia-Pei Lin, Chin-Feng Chang, Min-Chi Hsieh, Chiu-Yu Cheng, Ying-Chien Chung

    Asparagus cochinchinensis root (ACR) is used in traditional Chinese medicine. In this study, ACR was first extracted with 25% ethyl acetate (EA) and then fermented by Aspergillus oryzae to enhance its antioxidant activity and evaluate its potential antityrosinase activity. The physiological activity and cytotoxicity of A. oryzae-fermented ACR extract, along with its antityrosinase activity and effects on melanogenic factor levels in human epidermal melanocytes (HEMs), were analyzed and compared with those of the unfermented extract. The results showed that the physiological activity of the fermented extract in vitro or in cells was significantly higher than that of the unfermented extract. The IC50 values for 2,2-diphenyl-1-picrylhydrazine radical scavenging activity, reducing power, and antityrosinase activity in vitro for the fermented extract were 250.6 ± 32.5, 25.7 ± 3.5, and 50.6 ± 3.1 mg/L, respectively. The fermented extract favored cellular antityrosinase activity with low melanin production in human melanoma cells compared with the unfermented extract. The inhibitory mechanism of melanin synthesis by unfermented extract was independent of the tested melanogenesis-related proteins. However, the inhibitory mechanism of the fermented extract was possibly caused by synergistic inhibition of these proteins. Thus, A. oryzae-fermented ACR extract may be used for developing new health food or cosmetic ingredients.

  • Optimization of a dual-functional biocatalytic system for continuous hydrolysis of lactose in milk

    Publication date: Available online 8 August 2018

    Source: Journal of Bioscience and Bioengineering

    Author(s): Heng Li, Yuting Cao, Shuai Li, Yun Jiang, Jianqi Chen, Zhuofu Wu

    In this study, an amino-functionalized silica matrix encapsulating β-galactosidase was first synthesized in situ, with subsequent covalent anchoring of lysozyme to the outer part of the amino-grafted matrix. Fourier transform infrared (FTIR) spectra verified that β-galactosidase was successfully encapsulated. Meanwhile, the co-immobilized enzymes were demonstrated to retain suitable enzymatic activities and outstanding operational stability during successive reaction cycles. Furthermore, when used for lactose removal from skim milk, the packed-bed column system achieved both a high lactose hydrolysis rate and microbial inactivation ratio during 30 days of continuous operation. Notably, this system exhibited favorable stability during 60 days of continuous hydrolysis of lactose in solution and thus may be appropriate for further development for use in industrial lactose removal from milk.

    Graphical abstract

    Image 1