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Media Composition (media + composition)
Selected AbstractsThe effect of carbon and nitrogen sources on bovicin HC5 production by Streptococcus bovis HC5JOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2009A.A.T. De Carvalho Abstract Aims:, To investigate the effect of media composition and agroindustrial residues on bovicin HC5 production by Streptococcus bovis HC5. Methods and Results:, Batch cultures of S. bovis HC5 were grown in basal medium containing different carbon and nitrogen sources. The activity of cell-free and cell-associated bovicin HC5 was determined in culture supernatants and acidic extracts obtained from cell pellets, respectively. Streptococcus bovis HC5 produced bovicin using a variety of carbon and nitrogen sources. The highest specific activity was obtained in media containing 16 g l,1 of glucose, after 16 h of incubation. The peak in cell-free and cell-associated bovicin HC5 activity was detected when S. bovis HC5 cultures reached stationary phase. The bovicin HC5 specific activity and bacterial cell mass increased approximately 3-fold when yeast extract and trypticase (0·5 and 1·0 g l,1, respectively) were added together to the basal medium. Streptococcus bovis HC5 cultures produced bovicin HC5 in cheese whey and sugar cane juice and maximal volumetric productivity was obtained after 12 h of incubation. Conclusions:,Streptococcus bovis HC5 is a versatile lactic acid bacterium that can utilize several carbon and nitrogen sources for bovicin HC5 production. This bacterium could be a useful model to study bacteriocin production in the rumen ecosystem. Significance and Impact of the Study:, The use of agroindustrial residues as carbon sources could have an economical impact on bovicin HC5 production. To our knowledge, this is the first report to show the use of sugar cane juice for bacteriocin production by lactic acid bacteria. [source] Production and Stability Studies of a Neurotoxin Produced by Clostridium sp.JOURNAL OF FOOD SCIENCE, Issue 3 2006ABSTRACT: A neurotoxigenic Clostridium sp. (RKD) isolated from intestine of decaying fish produced a neurotoxin that was neutralized by botulinum antitoxin (A+B+E) when tested by mouse protection bioassay. An amplicon of expected size (approximately 700 bp) was generated with primers specific for BoNT/B. Toxin was maximally released in the culture supernatant in the late stationary phase and was dependent on media composition. Growth was optimal in trypticase peptone yeast-extract glucose (TPYG) medium in a pH range of 7.5 to 8.0 and at a temperature between 35°C to 40°C while toxin production was optimum at 37°C (3 to 4 × 103 minimum lethal dose per milliliter) without any protease treatment. There was no correlation between growth and toxin production when cells were grown in media containing different concentrations of NaCl (0% to 5%). Toxin in the culture supernatant was more stable (50% reduction at 50°C in 90 min) than the partially purified fraction. Toxicity was destroyed gradually after increasing the number of freeze-thaw cycles and was almost completely inactivated after 5 cycles. It was completely inactivated by overnight treatment of 1 N NaOH while it retained 1.5% activity with a similar treatment with 1 N HCl. [source] The impact of media composition and petite mutation on the longevity of a polyploid brewing yeast strainLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2000C.D. Powell Ageing in Saccharomyces cerevisiae is a finite phenomenon, determined by replicative, rather than chronological lifespan. Yeast physiological condition is known to influence industrial fermentation performance, however, until recently cellular senescence has not been considered as a brewing yeast stress factor. A polyploid lager yeast (BB11) and a brewery isolate, exhibiting petite mutation were analysed for longevity. It was observed that mitochondrial deficiency induced a reduction in lifespan. In addition, replicative capacity was perceived to be dependent on environmental conditions. [source] Elevated Histone H1 (MPF) and Mitogen-activated Protein Kinase Activities in Pig Oocytes Following In Vitro Maturation do not Indicate Cytoplasmic MaturationREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2009MA Setiadi Contents Effects of different media (TCM 199 + BSA, TCM 199 + FCS, TCM 199 + NBCS, Whitten's medium + BSA) supplemented with estradiol-17, and two isolated and everted follicle shells on MPF and MAP kinase activities and the sensitivity to parthenogenetic activation of pig oocytes were examined at the end of culture (48 h). Elevated (P < 0.05) activities of MAP kinase were recorded in metaphase II oocytes following culture in Whitten's medium, whereas MPF levels were lowest (P < 0.05) in MII oocytes matured in TCM 199 supplemented with BSA. Oocytes matured in TCM 199 based media showed higher (P < 0.05) activation rates when compared to oocytes incubated in Whitten's medium. Whitten's medium supplemented with different protein sources (amino acids, FCS, BSA) was used to study the effects of different exposure periods to eCG/hCG stimulation on MPF and MAP kinase activities and in vivo fertilisability following culture for 48 h. MPF and MAP kinase activities were significantly increased by eCG/hCG stimulation of COCs during maturation. Further, the continuous presence of eCG/hCG during culture (48 h) significantly increased the levels of both kinases in comparison to stimulation by gonadotrophins alone during the first 24 h of incubation. In vivo fertilisation of oocytes matured in Whitten's medium supplemented with eCG/hCG for 24 or 48 h led to a significant retardation of early embryonic development compared to ovulated oocytes. In conclusion, media composition and gonadotrophin stimulation affect MPF/MAP kinase activities and the susceptibility to parthenogenetic activation of IVM oocytes. However, elevated kinase levels in pig oocytes following culture do not indicate complete cytoplasmic maturation. [source] A Procedure for High-Yield Spore Production by Bacillus s ubtilisBIOTECHNOLOGY PROGRESS, Issue 4 2005Sandra M. Monteiro Bacillus subtilis spores have a number of potential applications, which include their use as probiotics and competitive exclusion agents to control zoonotic pathogens in animal production. The effect of cultivation conditions on Bacillus subtilis growth and sporulation was investigated in batch bioreactions performed at a 2-L scale. Studies of the cultivation conditions (pH, dissolved oxygen concentration, and media composition) led to an increase of the maximum concentration of vegetative cell from 2.6 × 109 to 2.2 × 1010 cells mL - 1 and the spore concentration from 4.2 × 108 to 5.6 × 109 spores mL - 1. A fed-batch bioprocess was developed with the addition of a nutrient feeding solution using an exponential feeding profile obtained from the mass balance equations. Using the developed feeding profile, starting at the middle of the exponential growth phase and finishing in the late exponential phase, an increase of the maximum vegetative cell concentration and spore concentration up to 3.6 × 1010 cells mL - 1 and 7.4 × 109 spores mL - 1, respectively, was obtained. Using the developed fed-batch bioreaction a 14-fold increase in the concentration of the vegetative cells was achieved. Moreover, the efficiency of sporulation under fed-batch bioreaction was 21%, which permitted a 19-fold increase in the final spore concentration, to a final value of 7.4 × 109 spores mL - 1. This represents a 3-fold increase relative to the highest reported value for Bacillus subtilis spore production. [source] Optimization of Fermentation Conditions for Preparation of Polygalacturonic Acid Transeliminase by Erwinia carotovora IFO3830BIOTECHNOLOGY PROGRESS, Issue 2 2001Fengping Ding This paper is concerned with optimization of the fermentation conditions for preparation of alkaline pectin lyase (poly-galacturonic acid trans-eliminase, PATE) by Erwinia carotovoraIFO3830 (E.C.IFO3830). The orthogonal matrix method was adopted as the experimental design method for media. The effects of media composition on the growth rate of E.C.IFO3830 are in the order of pectin > KH2PO4/Na2HPO4 > MgSO4 > (NH4)2SO4 > glucose > L -glutamate sodium, and those on PATE activity are in the order of glucose > pectin > L -glutamate sodium > KH2PO4/Na2HPO4 > MgSO4 > (NH4)2SO4. The strain of E.C.IFO3830 grows quickly and easily near an initial pH of 7.0, and especially at the alkaline range of pH 7.0,8.0. The growth rate profiles indicate that E.C.IFO3830 grows very quickly; its generation time t1/2 is about 0.2 h. The appropriate fermentation period is about 10,20 h for a high level productivity of biomass and 25,35 h for high productivity of PATE enzyme. [source] | ||||||||||