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Acetic Acid Production (acetic + acid_production)
Selected AbstractsEFFECT OF PHYSICAL FACTORS ON ACETIC ACID PRODUCTION IN BRETTANOMYCES STRAINSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2005C. CASTRO-MARTINEZ ABSTRACT Four species of Brettanomyces (intermedius, bruxellensis, custersianus, clausenii) were examined to ascertain their acetic acid production capacity. The results showed that B. bruxellensis was the strain with the best volumetric productivity ,and ,specific ,production ,rate ,(P = 0.065 gL,1 h,1; ,Vp = 0.43 gg,1h,1). The best kinetic parameters were reached (P = 0.133 gL,1 h,1; Yp/s = 0.23; Pmax = 11.64 gL,1) ,at ,an ,airflow ,of ,288 Lh,1,(0.6 vvm, ,OTR = 124 mgO2L,1,h,1), and substrate inhibition was not observed. The influence of temperature and agitation on acetic acid production by B. bruxellensis in a glucose medium was investigated at different levels, 26, 30, 34C and 250, 350, 450 rpm, respectively. Temperature and agitation were shown to be deci-sive factors (P < 0.05) in acetic acid production at 288 Lh,1(0.6 vvm, OTR = 124 mgO2L,1 h). The optimal conditions for a high volumetric productivity were 30C and 250 rpm, respectively. [source] Effects of selected lactic acid bacteria on the characteristics of amaranth sourdoughJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2010Mario Jekle Abstract BACKGROUND: As the processing of amaranth in baked goods is challenging, the use of sourdough fermentation is a promising possibility to exploit the advantages of this raw material. In this study the fermentation properties of Lactobacillus plantarum, Lactobacillus paralimentarius and Lactobacillus helveticus in amaranth-based sourdough were examined in order to validate them as starter cultures. pH, total titratable acidity (TTA) and lactic/acetic acid ratio of the sourdough and sensory properties of the resulting wheat bread were evaluated using fermentation temperatures of 30 and 35 °C. RESULTS: While fermentation pH, TTA and lactic acid concentration showed small variations with the use of L. plantarum and L. paralimentarius, L. helveticus reached the most intensive acidification after initial adaptation to the substrate. Acetic acid production was independent of lactic acid metabolism. Furthermore, the lactic/acetic acid ratio exceeded recommendation by 10,35 times (fermentation quotient 25,82). Sensory evaluation showed no significant differences between the two fermentation temperatures but differences among the three micro-organisms. CONCLUSION: The results provide relevant information on the fermentation properties required of a customised starter for amaranth flour. Copyright © 2010 Society of Chemical Industry [source] Modeling and Biokinetics in Anaerobic Acidogenesis of Starch-Processing Wastewater to Acetic AcidBIOTECHNOLOGY PROGRESS, Issue 2 2004Johng-Hwa Ahn Starch-processing wastewater was anaerobically treated to produce acetic acid in laboratory-scale, continuously stirred tank reactors. The optimal conditions, in which the maximum acetic acid production occurred, were 0.56 d hydraulic retention time, pH 5.9, and 36.1 °C. Acetic acid production at the optimum conditions was 672 ± 20 mg total organic carbonequivalent L,1, which indicated a 75% conversion efficiency of influent total organic carbon into acetic acid. A fourth order Runge-Kutta approximation was used to determine the Monod kinetics of the acidogens by using unsteady-state data from continuous unsteady-state experiments at the optimum conditions. The model outputs and experimental data fit together satisfactorily, suggesting that the unsteady-state approach was appropriate for the evaluation of acidogenic biokinetics. These included ,m, Ks, Y, and kd, which were evaluated as being 0.13 h,1, 25 mg total carbohydrate (TC) L,1, 0.38 mg volatile suspended solid mg,1 TC, and 0.002 h,1, respectively. [source] Production of d -(,)-3-hydroxyalkanoic acid by recombinant Escherichia coliFEMS MICROBIOLOGY LETTERS, Issue 1 2003Kai Zhao Abstract Pathways for extracellular production of chiral d -(,)-3-hydroxybutyric acid (3HB) and d -(,)-3-hydroxyalkanoic acid (mcl-3HA) were constructed by co-expression of genes of ,-ketothiolase (phbA), acetoacetyl-CoA reductase (phbB) and 3-hydroxyacyl-ACP CoA transacylase (phaG), respectively, in Escherichia coli strain DH5,. The effect of acrylic acid and glucose on production of both 3HB and mcl-3HA was investigated. It was found that the addition of acrylic acid significantly increased production of 3HB and mcl-3HA consisting of 3-hydroxyoctanoic acid and 3-hydroxydecanoic acid in a ratio of 1:3 from 199 mg l,1 to 661 mg l,1 and from 27 mg l,1 to 135 mg l,1, respectively, in shake flask studies when glucose was present in the medium at the very beginning of fermentation. The timing of glucose addition had no effect on 3HB production. In contrast, mcl-3HA production was affected by glucose addition, an mcl-3HA concentration of 193 mg l,1 was obtained when glucose was added to the culture at 12 h. A more than seven-fold increase was obtained when compared with that in medium containing glucose at the beginning of fermentation. However, a decrease in production of 3HB and mcl-3HA was found when glucose was added at 12 h to the culture containing acrylic acid. The repressive effect of acrylic acid on acetic acid production was also evaluated and discussed. [source] Single QTL mapping and nucleotide-level resolution of a physiologic trait in wine Saccharomyces cerevisiae strainsFEMS YEAST RESEARCH, Issue 6 2007Philippe Marullo Abstract Natural Saccharomyces cerevisiae yeast strains exhibit very large genotypic and phenotypic diversity. However, the link between phenotype variation and genetic determinism is still difficult to identify, especially in wild populations. Using genome hybridization on DNA microarrays, it is now possible to identify single-feature polymorphisms among divergent yeast strains. This tool offers the possibility of applying quantitative genetics to wild yeast strains. In this instance, we studied the genetic basis for variations in acetic acid production using progeny derived from two strains from grape must isolates. The trait was quantified during alcoholic fermentation of the two strains and 108 segregants derived from their crossing. A genetic map of 2212 markers was generated using oligonucleotide microarrays, and a major quantitative trait locus (QTL) was mapped with high significance. Further investigations showed that this QTL was due to a nonsynonymous single-nucleotide polymorphism that targeted the catalytic core of asparaginase type I (ASP1) and abolished its activity. This QTL was only effective when asparagine was used as a major nitrogen source. Our results link nitrogen assimilation and CO2 production rate to acetic acid production, as well as, on a broader scale, illustrating the specific problem of quantitative genetics when working with nonlaboratory microorganisms. [source] Analysis of acetic acid productivity in a continuous two-stage bioreactor with cell recyclingJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2005Akio Nishiwaki Abstract The performance of a two-stage system with cell recycling and fresh feed at each stage is studied numerically for continuous acetic acid production. In this system, both filtrate and bleed broth from the first stage are supplied to the second fermenter. At high substrate conversions, this configuration is found to provide higher acetic acid productivities than either a previous configuration where only the first-stage bleed broth is fed to the second stage or a single recycle chemostat at the same bleed ratios. Copyright © 2005 Society of Chemical Industry [source] EFFECT OF PHYSICAL FACTORS ON ACETIC ACID PRODUCTION IN BRETTANOMYCES STRAINSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2005C. CASTRO-MARTINEZ ABSTRACT Four species of Brettanomyces (intermedius, bruxellensis, custersianus, clausenii) were examined to ascertain their acetic acid production capacity. The results showed that B. bruxellensis was the strain with the best volumetric productivity ,and ,specific ,production ,rate ,(P = 0.065 gL,1 h,1; ,Vp = 0.43 gg,1h,1). The best kinetic parameters were reached (P = 0.133 gL,1 h,1; Yp/s = 0.23; Pmax = 11.64 gL,1) ,at ,an ,airflow ,of ,288 Lh,1,(0.6 vvm, ,OTR = 124 mgO2L,1,h,1), and substrate inhibition was not observed. The influence of temperature and agitation on acetic acid production by B. bruxellensis in a glucose medium was investigated at different levels, 26, 30, 34C and 250, 350, 450 rpm, respectively. Temperature and agitation were shown to be deci-sive factors (P < 0.05) in acetic acid production at 288 Lh,1(0.6 vvm, OTR = 124 mgO2L,1 h). The optimal conditions for a high volumetric productivity were 30C and 250 rpm, respectively. [source] Fermentation of Reconstituted Skim Milk Supplemented with Soy Protein Isolate by Probiotic OrganismsJOURNAL OF FOOD SCIENCE, Issue 2 2008T.T. Pham ABSTRACT:, Utilization of lactose and production of organic acid were determined in reconstituted skim milk (RSM) and RSM supplemented with soy protein isolate (SPI) (RSMS) by 6 probiotic organisms, including L. acidophilus 4461, L. acidophilus 4962, L. casei 290, L. casei 2607, B. animalis subsp. lactis bb12, and B. longum 20099. The viable counts of probiotic organisms of RSM and RSMS were enumerated and pH measured during fermentation. Our results showed that 3% to 10% more lactose was utilized by all the 6 probiotic microorganisms from RSMS than RSM. All 6 probiotic organisms produced significantly more acetic acid in RSMS than RSM. However, the viable microbial populations in RSMS were lower than those in RSM due to lower pH of the former. It appears that addition of SPI enhanced lactose utilization and acetic acid production but slightly reduced the lactic acid production and the growth of probiotic microorganisms. [source] Modeling and Biokinetics in Anaerobic Acidogenesis of Starch-Processing Wastewater to Acetic AcidBIOTECHNOLOGY PROGRESS, Issue 2 2004Johng-Hwa Ahn Starch-processing wastewater was anaerobically treated to produce acetic acid in laboratory-scale, continuously stirred tank reactors. The optimal conditions, in which the maximum acetic acid production occurred, were 0.56 d hydraulic retention time, pH 5.9, and 36.1 °C. Acetic acid production at the optimum conditions was 672 ± 20 mg total organic carbonequivalent L,1, which indicated a 75% conversion efficiency of influent total organic carbon into acetic acid. A fourth order Runge-Kutta approximation was used to determine the Monod kinetics of the acidogens by using unsteady-state data from continuous unsteady-state experiments at the optimum conditions. The model outputs and experimental data fit together satisfactorily, suggesting that the unsteady-state approach was appropriate for the evaluation of acidogenic biokinetics. These included ,m, Ks, Y, and kd, which were evaluated as being 0.13 h,1, 25 mg total carbohydrate (TC) L,1, 0.38 mg volatile suspended solid mg,1 TC, and 0.002 h,1, respectively. [source] | |||||||||||||