Growth Kinetics of Saccharomyces cerevisiae and Tape Yeast on the Cassava Pulp Fermentation and Its Granular Morphology Changes (original) (raw)
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Enzyme and Microbial Technology, 1996
A fermentation medium based on waste cassava starch hydrolysate and a four-phase feeding strategy for a fed-batch culture of Baker's yeast Saccharomyces cerevisiae are presented. Cassava starch isolated from the wastewater produced in processing of cassava mash into gari was liquefied with a thermostable 1.4-α-d-glucanohydrolase (EC 3.2.1.1) in the presence of 100 ppm Ca2+ at 80°C and pH 6.1–6.3 for one h. The liquefied material was saccharified with 1.4-α-d-glucan glucohydrolase (EC 3.2.1.3) at 55°C and pH 5.5 for two h. Over 98% of the starch was hydrolyzed; about 80.7% of the hydrolysate was glucose. The fermentation feeding profile which was based on a desired specific growth rare range of 0.18–0.23 h−1, a biomass yield coefficient of 0.5 g g−1, and a feed substrate concentration of 200 g l−1 was implemented manually using the cassava hydrolysate feed in test experiments and glucose feed in control experiments. The fermentation off-gas was analyzed on-line by mass spectrometry for the calculation of the oxygen uptake rate, the carbon dioxide evolution rate, and the respiratory quotient. Off-line determinations of biomass, ethanol, and glucose were done, respectively, by dry weight, gas chromatography, and spectrophotometry. Cell mass concentrations of 50–58 g l−1 were achieved in all experiments within 28 h of which the last 15 h were in the fed-batch mode. The average biomass yields for the cassava and glucose media were identical at 0.49 g g−1. No significant differences were observed between the leavening activities of the products of the test, the control media, and a commerical preparation of instant active dry yeast. Waste cassava starch hydrolysate was established as a suitable low cost replacement for glucose in the production of baking-quality yeast.
Performance of yeast cultures in cassava wastes
Journal of Biochemical Technology, 2012
Yeasts isolated from palm wine were cultured in media of varying cassava peel concentration and their growths were monitored. Thereafter, the yeasts were subjected to crude protein analysis. The performance in terms of crude protein and growth rate using monod model was studied. The results show that the maximum crude protein content of about 4% was obtained at 1.5% cassava peel concentration for media unamended with ammonium sulphate. For cassava peel media amended with ammonium sulphate, the maximum crude protein content of about 7% was obtained, also, at 1.5% cassava peel concentration. The maximum specific growth rates were 0.38 day-1 for 1%, 0.47 day-1 for 1.5% and 0.41 day-1 for 2% for amended cassava peel media. For cassava peel media amended with ammonium sulphate, the maximum specific growth rates were 0.9day-1 for 1%, 0.94 day-1for 1.5% and 0.96 day-1 for 2%.
Study of Starch Degradation by Yeasts During Fermentation for Using in Animal Feed
Applied Biochemistry and Biotechnology, 2010
Sixteen amylolytic yeasts, drawn from culture collections or isolated from different environments, were used in the present study. Experiments were performed to evaluate the starch degradation due to exocellular activity. The culture media of growth was optimized to find the maximum activity, and some strains produced an extracellular amylolytic enzyme when cultured in presence of starch in the medium. On the other hand, one yeast showed activity in cell extract when cultured under varying conditions in a bench bioreactor; this strain would thus be suitable for use as an animal feed supplement, both as a source of proteins and nucleic acids and in terms of its amylolytic activity.
Biomass production of Saccharomyces cerevisiae in batch culture was studied as a function of three variables: total sugar and nitrogen concentration and airflow rates, which have a determinant influence on the response. So, the growth of S. cerevisiae was higher for the highest levels of nitrogen source concentration (20 g l -1 ) and air flow (3 l h -1 ) and lower values of total sugar concentration (50 g l -1 ). Production of single cell protein (SCP) was investigated under solid state fermentation on sugar cane bagasse as a function of three variables: size particle, initial moisture and sugar content. An initial moisture content of 74.3%, initial sugar concentration of 32.82 g g -1 and 5 mm of size particle were optimum for SCP production in SSF. Under the optimized conditions, the SCP production was 2.69%. The empirical models obtained for both submerged liquid and solid state fermentation allow the suitable orientation for biomass production improvement.
Ife Journal of Science, 2008
Yeasts are microorganisms in which the unicellular form is conspicuous and outstanding. In this group are the versatile strains of Saccharomyces cerevisiae (Baker's yeast). The local production of Baker's yeast becomes necessary in Nigeria to replace imported ones being used currently in the industries. The utilization of cassava as a feedstock for the production of baker's yeast using fed-batch fermentation process was investigated. Starch was extracted from freshly harvested cassava tubers and hydrolyzed into fermentable sugar using the enzyme-enzyme method. From the initial starch slurries of 8.84% and 12.40% concentrations, Sugar concentrations of 8.57% and 12.0% respectively were attained. These hydrolysates were used as substrates for the aerobic cultivation of S. cerevisiae under fed-batch conditions for 24 hours with a constant feed rate of 1.1174 L/h. The result obtained revealed that biomass, reducing sugar as well as ethanol concentration increased with fermen...
Evaluation of Growth Kinetics and Biomass Yield of Baker's Yeast on Potato Flour
Food Science and Engineering
The study aims to evaluate the growth kinetics of two different Baker’s yeast (S. cerevisiae) strains and to establish regression models for predicting and optimizing of the growth conditions of the strains. Two yeast strains of S. cerevisiae; one was commercial strain (CS) and another was isolated from traditional dry wine residue of Madhupur region, Bangladesh (MS), were used in the study. The effects of four different factors viz., time, temperature, agitation and the potato powder concentrations were assessed. The performance of the growth of the strains was monitored using three responses like OD at 600 nm, ethanol production and biomass yield (g.L-1). Fractional factorial design (24-1) was used to generate the experimental trials as well as to analyze the data to design a geometrical representation. The highest value of optical density, ethanol and biomass production for S. cerevisiae (CS) were obtained 1.439, 6.56 (g.L-1) and 0.39 (g.L-1) respectively, and for S. cerevisiae (...
Asian J Agric & Biol., 2019
Solid-state fermentation using Saccharomyces cerevisiae is the most optimal method to increase protein content and reduce cyanide content of cassava pulp to use it as a food ingredient. This research aimed to evaluate the effect of fermentation time on the growth dynamics of S. cerevisiae, chemical, amylographic profile and granular morphology changes on cassava pulp fermentation. The results of the study revealed that S. cerevisiae was able to grow logarithmic up to 72 hours of fermentation with starch and dietary fiber as a nutrition source and causes changes in viscosity profile and granular morphology. The increase in the total number of cells (viable cell and dead cell) will increase single cell protein biomass, which will increase the protein content to 7.07% and reduce cyanide content to 8.78 ppm.
Ecological, biological and biotechnological aspects of Saccharomyces Cerevisiae biomass production
Caspian Journal of Environmental Sciences, 2024
Baker's yeast Saccharomyces Cerevisiae (S. cerevisiae), belonging to the Ascomycota yeast type and being facultatively anaerobic, plays a key role in ecology, fundamental and evolutionary biology, biotechnology and industrial fermentations, in particular, in the production of fermented food and beverages. Saccharomyces Cerevisiae (S. cerevisiae) grows on substrates with a high sugar content and is an important ingredient in flour bakery and confectionery products. In yeast, glucose metabolism is carried out by oxidation or fermentation, in the first case, this leads to cell growth, and in the second – to the formation of ethanol. A high concentration of glucose or a low concentration of oxygen in the nutrient medium stimulates the Crabtree effect, which inhibits cell growth and increases the formation of ethanol. The article reveals the fundamental and applied biology of baker's yeast Saccharomyces Cerevisiae and reveals the technological methods of enriching beet molasses with nutrients in order to increase the yield of biomass. It is shown that the successful commercial production of baking yeast Saccharomyces Cerevisiae is determined by biological (Saccharomyces Cerevisiae yeast strain with good breeding indicators; crop size, etc.) and technological (molasses quality: nature, composition, and concentration of substrate; cheap, suitable for cultivation carbon source; easily controlled cultivation process to obtain the most viable biomass, physico-chemical conditions of cultivation, primarily temperature, pH; cultivation period; development of the canning process, etc.) condıtıons. In industrial production, Saccharomyces Cerevisiae baker's yeast is obtained either from collection centres at the initial stages, or its own strains are isolated and cultivated, and subsequently, cultures are maintained, ensuring consistency of quality and productivity. The breeding characteristics of baker's yeast are: the ability to adapt to changing cultivation conditions, because the composition of molasses has high variability; the efficiency of respiratory metabolism during yeast production, which determines the yield of biomass; biomass production; cell growth rate; the ability to ferment; ability to quickly convert carbohydrates into CO2; ethanol production; dehydration; the volume of the final product, structure, colour (carbohydrates, amino acids); stress resistance to environmental conditions, in particular, to cold stress; shelf life (acids, glycerine). Today, as shown in the article, technological methods for enriching beet molasses with nutrients have different solutions. Molasses is enriched with cereals (cottonseed, cereal germs, legumes, peanut fodder cake), plant hormones, specific growth factors, animal products (milk, whey, animal waste), ammonium sulphate, malt (expensive), aqueous ammonia, ammonium salts. The enrichment of molasses with nutrients based on the use of cereals, glucose syrup obtained from corn, date syrup, whey, cassava, forestry, and agricultural waste has commercial potential, since these approaches do not require special processing requirements and provide low production costs (exception: forestry waste). In the technology of Saccharomyces Cerevisiae biomass production, a population of diploid cells is used, since compared with haploid cells they are genetically more stable, characterized by faster and more active metabolism, and larger sizes.
2018 UBT International Conference, 2018
Biological systems are very complex regarding their kinetic behavior. There are many models that intend to predict fermentation performance, although Monod equation remains the best model. A detailed investigation of batch fermentation process at room temperature for two different types of yeast Saccharomyces carlsbegensis and Saccharomyces cerevisiae was carried out. Batch fermentation experiments were carried in 1 liter bioreactors, in the same medium, time and fermentation conditions. Kinetic constants were used to compare fermentation performance under similar conditions. Kinetic parameters investigation was done based on growth kinetics, ethanol productivity and substrate consumption (glucose) using computer simulation for different kinetic models. There are some notable differences based on kinetic models. Although two types of yeast strain leave the same remain extract in the end of fermentation, fermentation dynamics differ from each other. Saccharomyces carlsbengensis has h...