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Jin-Song Gong, Qiang Zhang, Bing-Chen Gu, Ting-Ting Dong, Heng Li, Hui Li, Zhen-Ming Lu, Jin-Song Shi, Zheng-Hong Xu
The constitutively expression system for P. putida nitrilase was firstly constructed to improve the nicotinic acid production and reduce the production costs. High density culture strategy was employed to enhance the biomass and nitrilase production of recombinant strain. The total nitrilase activity reached up to 654 U·mL-1 without the induction. 541 g·L-1 nicotinic acid was accumulated via fed batch mode of substrate feeding through 290 min of conversion.
March 30, 2018: Bioresource Technology
Brigitte Mukarunyana, Jack van de Vossenberg, Jules B van Lier, Peter van der Steen
Removal of nitrogen from wastewater without using electricity consuming aerators was previously observed in photo-bioreactors with a mixed algal-bacterial biomass. Algammox is the particular process based on algae, ammonium oxidizing organisms and anammox bacteria. In this research the activity of anammox bacteria in such an oxygen-producing environment was tested, as well as the effect of short-duration increase in dissolved oxygen (DO) to values potentially inhibiting anammox activity. Sequencing batch photo-bioreactors were fed with settled domestic wastewater enriched with ammonium (200mgNH4 + -N/L) and exposed to light within the photosynthetic active range with intensity of about 500μmol/m2 ·s...
April 10, 2018: Science of the Total Environment
Wen-Hsing Chen, Yan-Ru Zeng
This study aimed to establish a mathematical modeling to evaluate the inhibitory effect of phenolic derivatives on acetone-butanol-ethanol (ABE) fermentation by Clostridium saccharoperbutylacetonicum N1-4. Vanillin, 4-hydroxybenzoic acid, and syringaldehyde were selected to represent guaiacyl, hydroxyphenyl, and syringyl phenols, respectively, to be examined in a series of fed-batch experiments. Results show the presence of phenolic derivatives blocked the pathway of the assimilation of organic acids and reduced cell growth and glucose utilization...
April 5, 2018: Bioresource Technology
Jakob Tophøj, Rasmus Dam Wollenberg, Teis Esben Sondergaard, Niels Thomas Eriksen
Heterotrophic marine nanoflagellates are important grazers on bacteria in the water column. Some marine bacteria appear more resistant to grazing than do others. Marine nanoflagellates can be grown in the laboratory in batch cultures fed specific bacterial isolates. In some cultures, the flagellates appear unable to completely deplete the bacterial prey even when the bacterial strain otherwise is an excellent prey. This may indicate that some marine bacteria are able to induce defence mechanisms if they are grazed by nanoflagellates...
2018: PloS One
Alessandro Marco Lizzul, Aitor Lekuona-Amundarain, Saul Purton, Luiza Cintra Campos
This paper characterizes the strain Chlorella sorokiniana UTEX 1230 within a laboratory setting using a 1 L bubble column. The findings show that productivity can be trebled under mixotrophic conditions (from 0.2 g·L−1 ·d−1 to 0.66 g·L−1 ·d−1 ) with the addition of sodium acetate. The results also indicate that both the growth rate and final yield increase with the cultivation temperature, with most parameters showing an optimum in the range of 30–35 °C...
April 13, 2018: Biology
Peng Huang, Jinlei Shi, Qingwen Sun, Xianping Dong, Ning Zhang
Lysozymes are known as ubiquitously distributed immune effectors with hydrolytic activity against peptidoglycan, the major bacterial cell wall polymer, to trigger cell lysis. In the present study, the full-length cDNA sequence of a novel sea urchin Strongylocentrotus purpuratus invertebrate-type lysozyme (sp-iLys) was synthesized according to the codon usage bias of Pichia pastoris and was cloned into a constitutive expression plasmid pPIC9K. The resulting plasmid, pPIC9K-sp-iLys, was integrated into the genome of P...
April 13, 2018: Applied Biochemistry and Biotechnology
Luciana Fontes Coelho, Susan Michelz Beitel, Daiane Cristina Sass, Paulo Marcelo Avila Neto, Jonas Contiero
Bacillus coagulans arr4 is a thermotolerant microorganism with great biotechnological potential for l-(+)-lactic acid production from granulated sugar and yeast extract. The highest l-(+)-lactic acid production was obtained with Ca(OH)2 . The maximum production of l-(+)-lactic acid (206.81 g/L) was observed in exponential feeding using granulated sugar solution (900 g/L) and yeast extract (1%) at 50 °C, pH 6.5, and initial granulated sugar concentration of 100 g/L at 39 h. 5.3 g/L h productivity and 97% yield were observed, and no sugar remained...
April 2018: 3 Biotech
Apichai Sawisit, Surawee Jampatesh, Sirima Suvarnakuta Jantama, Kaemwich Jantama
Rice straw was pretreated with sodium hydroxide (NaOH) before subsequent use for succinate production by Escherichia coli KJ122 under simultaneous saccharification and fermentation (SSF). The NaOH pretreated rice straw was significantly enhanced lignin removal up to 95%. With the optimized enzyme loading of 4% cellulase complex + 0.5% xylanase (endo-glucanase 67 CMC-U/g, β-glucosidase 26 pNG-U/g and xylanase 18 CMC-U/g dry biomass), total sugar conversion reached 91.7 ± 0.8% (w/w). The physicochemical analysis of NaOH pretreated rice straw indicated dramatical changes in its structure, thereby favoring enzymatic saccharification...
March 30, 2018: Bioresource Technology
Zhaoyue Wang, Mingyue Jiang, Xuena Guo, Zhaozheng Liu, Xiuping He
BACKGROUND: 2-phenylethanol (2-PE) is an important aromatic compound with a lovely rose-like scent. Saccharomyces cerevisiae is a desirable microbe for 2-PE production but its natural yield is not high, and one or two crucial genes' over-expression in S. cerevisiae did not improve 2-PE greatly. RESULTS: A new metabolic module was established here, in which, permease Gap1p for L-phenylalanine transportation, catalytic enzymes Aro8p, Aro10p and Adh2p in Ehrlich pathway respectively responsible for transamination, decarboxylation and reduction were assembled, besides, glutamate dehydrogenase Gdh2p was harbored for re-supplying another substrate 2-oxoglutarate, relieving product glutamate repression and regenerating cofactor NADH...
April 11, 2018: Microbial Cell Factories
Seongjin Oh, David Tinotenda Mbiriri, Chaehwa Ryu, Kangheon Lee, Sangbuem Cho, Nag-Jin Choi
Objective: The goal of this study was to evaluate kenaf as a roughage source in vitro and its effects on meat quality of Hanwoo (Korean native) cattle. Methods: Three roughage materials, rice straw silage, ryegrass silage, and kenaf silage, were tested in a batch culture and feeding trial. Rumen fermentation parameters, including gas, pH, volatile fatty acid, and ammonia were analyzed. In the feeding trial, Hanwoo steers (373.5 ± 5.1 kg, n = 36, 11 month of age) were divided into three feeding groups (n = 12 each)...
April 12, 2018: Asian-Australasian Journal of Animal Sciences
Oscar Martínez, Antoni Sánchez, Xavier Font, Raquel Barrena
2-Phenylethanol (2-PE) and 2-phenethyl acetate (2-PEA) are important aroma compounds widely used in food and cosmetic industries due to their rose-like odor. Nowadays, due to the growing demand for natural products, the development of bioprocesses for obtaining value-added compounds has become of great significance. 2-PE and 2-PEA can be produced through the biotransformation of L-phenylalanine using the generally recognized as safe strain Kluyveromyces marxianus. L-phenylalanine bioconversion systems have been typically focused on submerged fermentation processes (SmF), but there is no information about other alternative productive approaches...
April 7, 2018: Applied Microbiology and Biotechnology
Yukai Suo, Mengmeng Ren, Xitong Yang, Zhengping Liao, Hongxin Fu, Jufang Wang
Butyric acid fermentation by Clostridium couples with the synthesis of acetic acid. But the presence of acetic acid reduces butyric acid yield and increases separation and purification costs of butyric acid. Hence, enhancing the butyrate/acetate ratio is important for economical butyric acid production. This study indicated that enhancing the acetyl-CoA to butyrate flux by overexpression of both the butyryl-CoA/acetate CoA transferase (cat1) and crotonase (crt) genes in C. tyrobutyricum could significantly reduce acetic acid concentration...
April 7, 2018: Applied Microbiology and Biotechnology
Na Yu, Li Tan, Zhao-Yong Sun, Hiroto Nishimura, Shouta Takei, Yue-Qin Tang, Kenji Kida
To investigate the effect of delignification on enzymatic saccharification and ethanol fermentation of sugarcane bagasse (SCB), NaClO, NaOH, and Na2 CO3 were used to prepare SCB with different lignin contents. We found that a lignin content of approximately 11% was sufficient for enzymatic saccharification and fermentation. Based on this result, an economical delignification pretreatment method using a combination of acid and alkali (CAA) was applied. Lignin content of 11.7% was obtained after CAA pretreatment with 0...
April 3, 2018: Waste Management
Mei Zhao, Dixuan Huang, Xiaojuan Zhang, Mattheos A G Koffas, Jingwen Zhou, Yu Deng
Adipic acid is an important dicarboxylic acid mainly used for the production of nylon 6-6 fibers and resins. Previous studies focused on the biological production of adipic acid directly from different substrates, resulting in low yields and titers. In this study, a five-step reverse adipate-degradation pathway (RADP) identified in Thermobifida fusca has been reconstructed in Escherichia coli BL21 (DE3). The resulting strain (Mad136) produced 0.3gL-1 adipic acid with a 11.1% theoretical yield in shaken flasks, and we confirmed that the step catalyzed by 5-carboxy-2-pentenoyl-CoA reductase (Tfu_1647) as the rate-limiting step of the RADP...
April 3, 2018: Metabolic Engineering
Zaigao Tan, Jong Moon Yoon, Anupam Chowdhury, Kaitlin Burdick, Laura R Jarboe, Costas D Maranas, Jacqueline V Shanks
Background: As a versatile platform chemical, construction of microbial catalysts for free octanoic acid production from biorenewable feedstocks is a promising alternative to existing petroleum-based methods. However, the bio-production strategy has been restricted by the low capacity of E. coli inherent fatty acid biosynthesis. In this study, a combination of integrated computational and experimental approach was performed to manipulate the E. coli existing metabolic network, with the objective of improving bio-octanoic acid production...
2018: Biotechnology for Biofuels
Rafael M Santos, Jean-Michel Kessler, Patrick Salou, Jose C Menezes, Antonio Peinado
Raman spectroscopy is a suitable monitoring technique for CHO cultivations. However, a thorough discussion of peaks, bands and region assignments to key metabolites and culture attributes, and the interpretability of produced calibrations is scarce. That understanding is vital for the long-term predictive ability of monitoring models, and to facilitate lifecycle management that comply with regulatory guidelines. Several fed-batch lab-scale mAb mammalian cultivations were carried out, with in-situ Raman spectroscopy used for process state estimation and attribute monitoring...
March 31, 2018: Biotechnology Progress
Giorgia Pagliano, Valeria Ventorino, Antonio Panico, Ida Romano, Alessandro Robertiello, Francesco Pirozzi, Olimpia Pepe
Dairy wastes can be conveniently processed and valorized in a biorefinery value chain since they are abundant, zero-cost and all year round available. For a comprehensive knowledge of the microbial species involved in producing biofuels and valuable intermediates from dairy wastes, the changes in bacterial and archaeal population were evaluated when H2 , CH4 and chemical intermediates were produced. Batch anaerobic tests were conducted with a mixture of mozzarella cheese whey and buttermilk as organic substrate, inoculated with 1% and 3% w/v industrial animal manure pellets...
March 26, 2018: Journal of Environmental Management
Ashish A Prabhu, Bibari Boro, Biju Bharali, Shuchishloka Chakraborty, V Venkata Dasu
BACKGROUND: Process development involving system metabolic engineering and bioprocess engineering has become one of the major thrust for the development of therapeutic proteins or enzymes. Pichia pastoris has emerged as a prominent host for the production of therapeutic protein or enzymes. Despite of producing high protein titers, various cellular and process level bottlenecks hinders the expression of recombinant proteins in P. pastoris. RESULT AND CONCLUSION: In the present review, we have summarized the recent developments in the expression of foreign proteins in P...
March 28, 2018: Current Pharmaceutical Biotechnology
Juli Wang, Haiying Yu, Xuejiao Song, Kun Zhu
Cyanobacteria alkane synthetic pathway has been heterologously constructed in many microbial hosts. It is by far the most studied and reliable alkane generating pathway. Aldehyde deformylating oxygenase (i.e., ADO, key enzyme in this pathway) obtained from different cyanobacteria species showed diverse catalytic abilities. This work indicated that single aldehyde reductase deletions were beneficial to Nostoc punctiforme ADO-depended alkane production in Escherichia coli even better than double deletions. Fatty acid metabolism regulator (FadR) overexpression and low temperature increased C18:1 fatty acid supply, and in turn stimulated C18:1-derived heptadecene production, suggesting that supplying ADO with preferred substrate was important to overall alkane yield improvement...
March 29, 2018: Journal of Industrial Microbiology & Biotechnology
Babett Wintsche, Nico Jehmlich, Denny Popp, Hauke Harms, Sabine Kleinsteuber
Anaerobic digestion (AD) is a complex multi-stage process relying on the activity of highly diverse microbial communities including hydrolytic, acidogenic and syntrophic acetogenic bacteria as well as methanogenic archaea. The lower diversity of methanogenic archaea compared to the bacterial groups involved in AD and the corresponding lack of functional redundancy cause a stronger susceptibility of methanogenesis to unfavorable process conditions such as trace element (TE) deprivation, thus controlling the stability of the overall process...
2018: Frontiers in Microbiology
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