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Sequential Fermentation

Niklas Tenhaef, Christian Brüsseler, Andreas Radek, René Hilmes, Pornkamol Unrean, Jan Marienhagen, Stephan Noack
It was found that Corynebacterium glutamicum ΔiolR devoid of the transcriptional regulator IolR accumulates high amounts of d-xylonate when cultivated in the presence of d-xylose. Detailed analyses of constructed deletion mutants revealed that the putative myo-inositol 2-dehydrogenase IolG also acts as d-xylose dehydrogenase and is mainly responsible for d-xylonate oxidation in this organism. Process development for d-xylonate production was initiated by cultivating C. glutamicum ΔiolR on defined d-xylose/d-glucose mixtures under batch and fed-batch conditions...
July 26, 2018: Bioresource Technology
Mahdy Elsayed, Abd El-Fatah Abomohra, Ping Ai, Dianlong Wang, Hamed M El-Mashad, Yanlin Zhang
Three routes; namely R1 representing direct anaerobic digestion (AD), R2 representing enzymatic hydrolysis followed by fermentation, distillation, then AD, and R3 representing AD of fermentation broth without distillation; of alkali pretreated rice straw were investigated. Results showed that sequential fermentation and AD effectively enhanced fibers degradation with significant changes in the composition. Fermentation through R2 resulted in ethanol yield of 87.4 g kg-1 dry straw. Maximum biogas yields of 286...
July 29, 2018: Bioresource Technology
Liqiu Su, Yanbing Shen, Menglei Xia, Zhihua Shang, Shuangping Xu, Xingjuan An, Min Wang
Androst-4-ene-3, 17-dione (AD) and androst-1, 4-diene-3, 17-dione (ADD) are generally produced by the biotransformation of phytosterols in Mycobacterium. The AD (D) production increases when the strain has high NAD+ /NADH ratio. To enhance the AD (D) production in Mycobacterium neoaurum TCCC 11978 (MNR M3), a rational strategy was developed through overexpression of a gene involved in the phytosterol degradation pathway; NAD+ was generated as well. Proteomic analysis of MNR cultured with and without phytosterols showed that the steroid C27-monooxygenase (Cyp125-3), which performs sequential oxidations of the sterol side chain at the C27 position and has the oxidative cofactor of NAD+ generated, played an important role in the phytosterol biotransformation process of MNR M3...
August 2, 2018: Journal of Industrial Microbiology & Biotechnology
Sarma Mutturi
There exist several optimization strategies such as sequential quadratic programming (SQP), iterative dynamic programing (IDP), stochastic-based methods such as differential evolution (DE), genetic algorithm (GA), particle swarm optimization (PSA), and ant colony optimization (ACO) for finding optimal feeding profile(s) during fed-batch fermentations. Here in the present study, flower pollination algorithm (FPA) which is inspired by the pollination process in terrestrial flowering plants has been used for the first time to find the optimal feeding profile(s) during fed-batch fermentations...
July 30, 2018: Bioprocess and Biosystems Engineering
Cansin Sackesen, Mayte Suárez-Fariñas, Ronaldo Sillva, Jing Lin, Stephanie Schmidt, Robert Getts, Gustavo Gimenez, Ebru A Yilmaz, Ozlem Cavkaytar, Betul Buyuktiryaki, Ozge Soyer, Galina Grishina, Hugh A Sampson
BACKGROUND: The majority of children with cow's milk allergy (CMA) tolerate baked-milk. However, reactivity to fermented-milk products like yogurt/cheese has not been previously evaluated. We sought to determine whether children with CMA could tolerate yogurt/cheese and whether a patient's IgE and IgG4 binding pattern to milk protein epitopes could distinguish clinical reactivity. METHODS: Four groups of reactivity were identified by OFC: Baked-milk reactive, Fermented-milk reactive, Whole-milk reactive and Outgrown...
July 29, 2018: Allergy
Javier Ruiz, Ignacio Belda, Beata Beisert, Eva Navascués, Domingo Marquina, Fernando Calderón, Doris Rauhut, Antonio Santos, Santiago Benito
Most wine aroma compounds, including the varietal fraction, are produced or released during wine production and derived from microbial activity. Varietal aromas, typically defined as terpenes and thiols, have been described as derived from their non-volatile precursors, released during wine fermentation by different yeast hydrolytic enzymes. The perception of these minority aroma compounds depends on the chemical matrix of the wine, especially on the presence of majority aroma compounds, such as esters or higher alcohols...
July 27, 2018: Applied Microbiology and Biotechnology
Albert L Müller, Claus Pelikan, Julia R de Rezende, Kenneth Wasmund, Martina Putz, Clemens Glombitza, Kasper U Kjeldsen, Bo Barker Jørgensen, Alexander Loy
Seafloor microorganisms impact global carbon cycling by mineralizing vast quantities of organic matter (OM) from pelagic primary production, which is predicted to increase in the Arctic because of diminishing sea ice cover. We studied microbial interspecies-carbon-flow during anaerobic OM degradation in arctic marine sediment using stable isotope probing. We supplemented sediment incubations with 13 C-labeled cyanobacterial necromass (spirulina), mimicking fresh OM input, or acetate, an important OM degradation intermediate, and monitored sulfate reduction rates and concentrations of volatile fatty acids (VFAs) during substrate degradation...
July 26, 2018: Environmental Microbiology
Digar Singh, Sunmin Lee, Choong Hwan Lee
The stochasticity of Aspergillus oryzae (Trivially: the koji mold) pan-metabolomes commensurate with its ubiquitously distributed landscapes, i.e. growth matrices have been seemed uncharted since its food fermentative systems are mostly being investigated. In this review, we explicitly have discussed the likely tendencies of A. oryzae metabolomes pertaining to its growth milieu formulated with substrate matrices of varying nature, composition, texture, and associated physicochemical parameters. We envisaged typical food matrices, namely, meju, koji, and moromi as the semi-natural cultivation models toward delineating the metabolomic patterns of the koji mold, which synergistically influences the organoleptic and functional properties of the end products...
July 23, 2018: Critical Reviews in Biotechnology
Jennifer R Bellon, Christopher M Ford, Anthony R Borneman, Paul J Chambers
Wine yeast breeding programs utilizing interspecific hybridization deliver cost-effective tools to winemakers looking to differentiate their wines through the development of new wine styles. The addition of a non- Saccharomyces cerevisiae genome to a commercial wine yeast can generate novel phenotypes ranging from wine flavor and aroma diversity to improvements in targeted fermentation traits. In the current study we utilized a novel approach to screen isolates from an evolving population for increased fitness in a S...
2018: Frontiers in Microbiology
Ping Li, Yingying Gao, Cailing Wang, Cui-Ying Zhang, Xuewu Guo, Dongguang Xiao
Diacetyl generates an aromatic off-flavor in wine at a high level. The present study expressed α-acetolactate decarboxylase (ALDB) from Lactobacillus plantarum and/or inactivated acetohydroxyacid synthase (Ilv6) in Saccharomyces uvarum, and the effects on diacetyl production and wine flavor in mutants were investigated through sequential fermentation and cofermentation in mixed cultures of S. uvarum and L. plantarum. The diacetyl content of WYDΔ6 (disrupted one ILV6 allele), WYSΔ6 ( ILV6 complete deletion), WYADΔ6 (disrupted one ILV6 allele with aldB expression), and WYASΔ6 ( ILV6 complete deletion with aldB expression) decreased by 25...
August 2, 2018: Journal of Agricultural and Food Chemistry
Hans Wijaya, Kengo Sasaki, Prihardi Kahar, Yopi, Hideo Kawaguchi, Takashi Sazuka, Chiaki Ogino, Bambang Prasetya, Akihiko Kondo
The aim of this study was to construct a cost-effective method for repeated bioethanol production using membrane (ultrafiltration permeation and nanofiltration concentration)-concentrated sweet sorghum juice by using flocculent Saccharomyces cerevisiae F118 strain. With low initial dry cell concentrations at around 0.28-0.35 g L-1 , the S. cerevisiae F118 strain provided an ethanol titer of 86.19 ± 1.15 g L-1 (theoretical ethanol yield of 70.77%), which was higher than the non-flocculent S. cerevisiae BY4741 strain at 33...
October 2018: Bioresource Technology
Aspasia Nisiotou, Georgios Sgouros, Athanasios Mallouchos, Constantinos-Symeon Nisiotis, Christos Michaelidis, Chryssoula Tassou, Georgios Banilas
The performance of two vineyard strains, Saccharomyces cerevisiae SacPK7 and Starmerella bacillaris StbPK9, was evaluated in laboratory and pilot scale fermentations of Cretan grape must under the following inoculation schemes: single inoculation of SacPK7 (IS), simultaneous inoculation of StbPK9 and SacPK7 (SM), and sequential inoculation of StbPK9 followed by SacPK7 (SQ). Un-inoculated (spontaneous) fermentations (SP) and fermentations inoculated with control S. cerevisiae strains (CS) were also conducted as reference...
September 2018: Food Research International
Yu Zhang, Changlei Xia, Mingming Lu, Maobing Tu
Background: Biomass prehydrolysates from dilute acid pretreatment contain a considerable amount of fermentable sugars for biofuels production. However, carbonyl degradation compounds present severe toxicity to fermentation microbes. Furans (such as furfural and hydroxymethylfurfural), aliphatic acids (such as acetic acid, formic acid and levulinic acid) and phenolic compounds (such as vanillin and syringaldehyde) have been suggested to be the main inhibitors in biomass prehydrolysates...
2018: Biotechnology for Biofuels
Mohit Bibra, Sudhir Kumar, Jia Wang, Aditya Bhalla, David R Salem, Rajesh K Sani
The aim of the present work was to use a thermophilic consortium for H2 production using lignocellulosic biomass in a single pot. The thermophilic consortium, growing at 60 °C utilized both glucose and xylose, making it an ideal source of microbes capable of utilizing and fermenting both hexose and pentose sugars. The optimization of pH, temperature, and substrate concentration increased the H2 production from 1.07 mmol H2 /g of prairie cordgrass (PCG) to 2.2 mmol H2 /g PCG by using the thermophilic consortium...
October 2018: Bioresource Technology
Zhaoyang Yuan, Guodong Li, Eric L Hegg
To improve sugar recovery and ethanol production from wheat straw, a sequential two-stage pretreatment process combining alkaline pre-extraction and acid catalyzed steam treatment was investigated. The results showed that alkaline pre-extraction using 8% (w/w) sodium hydroxide at 80 °C for 90 min followed by steam pretreatment with 3% (w/w) sulfur dioxide at 151 °C for 16 min was sufficient to prepare a substrate that could be efficiently hydrolyzed at high solid loadings. Moreover, alkaline pre-extraction reduced the process severity of steam pretreatment and decreased the generation of inhibitory compounds...
October 2018: Bioresource Technology
Brittany J Allison, Christopher W Simmons
Red grape pomace (RGP), a byproduct of red wine production, is an abundant food processing waste stream in California, rich in both anthocyanins, a class of red-blue pigments, and lignocellulose. Extraction of anthocyanins and biofuel production from RGP have been investigated independently, but no research has examined employing both strategies together for maximal valorization. In this study, anthocyanins were most effectively extracted from RGP at 80 °C. Convection- and vacuum-oven drying of the pomace were found to decrease anthocyanin yield, whereas lyophilization did not significantly affect yield...
August 1, 2018: Journal of Agricultural and Food Chemistry
Julián Carrillo-Reyes, Blanca Aidé Albarrán-Contreras, Germán Buitrón
Winery wastewaters are acidic effluents with high content of organic matter and nutrients. Different initial values of chemical oxygen demand (COD), ranging from 4 to 50 g L-1 , were tested in batch assays to evaluate the fermentative hydrogen production followed by a methane production step. The influence of adding a typical nutrient solution for hydrogen production was investigated. Nutrients include N-NH4 , Mg, Fe, Co, Mn, I, Ni, and Zn. The best hydrogen production potential was obtained at a COD of 50 g L-1 without nutrient addition...
June 18, 2018: Applied Biochemistry and Biotechnology
A R Ismail, S B El-Henawy, S A Younis, M A Betiha, N Sh El-Gendy, M S Azab, N M Sedky
AIM: The aim of this study was to isolate and identify lipolytic bacteria. Perform a statistical stepwise physicochemical optimization for maximum production of extracellular lipase and its validation in a bioreactor. METHODS AND RESULTS: Several lipolytic bacteria were isolated from petroleum hydrocarbon-polluted soil. The strain expressing the highest lipase activity (47 U ml-1 ) was genetically identified as Gram-positive Bacillus stratosphericus PSP8 (NCBI GenBank accession no...
June 16, 2018: Journal of Applied Microbiology
Dalia E Miranda-Castilleja, Ramón Á Martínez-Peniche, Montserrat Nadal Roquet-Jalmar, J Alejandro Aldrete-Tapia, Sofía M Arvizu-Medrano
Despite the importance of strain compatibility, most of the enological strain selection studies are carried out separately on yeasts and lactic acid bacteria (LAB). In this study, the enological traits and interactions between native yeasts and LAB were studied. The H2 S and acetic acid production, growth rates at 8 °C, killer phenotypes, flocculation, and tolerance to must and wine inhibitors were determined for 25 Saccharomyces yeasts. The ability to grow under two wine-like conditions was also determined in 37 LAB (Oenococcus oeni and Lactobacillus plantarum)...
July 2018: Journal of Food Science
Julian Lange, Eugenia Münch, Jan Müller, Tobias Busche, Jörn Kalinowski, Ralf Takors, Bastian Blombach
Zero-growth processes are a promising strategy for the production of reduced molecules and depict a steady transition from aerobic to anaerobic conditions. To investigate the adaptation of Corynebacterium glutamicum to altering oxygen availabilities, we conceived a triple-phase fermentation process that describes a gradual reduction of dissolved oxygen with a shift from aerobiosis via microaerobiosis to anaerobiosis. The distinct process phases were clearly bordered by the bacteria’s physiologic response such as reduced growth rate, biomass substrate yield and altered yield of fermentation products...
June 13, 2018: Genes
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