A dental biofilm forms a distinct environment where microorganisms live in a matrix of extracellular polysaccharides. The biofilm favors certain bacteria and creates a habitat that functions differently compared to planktonic bacteria. Reproducible model systems which help to address various questions related to biofilm formation, the process of caries development, and its prevention are needed...

Tuning recombinant protein expression is an approach which can be successfully employed for increasing the yield of recombinant protein production in high cell density cultures. On the other hand, most of the previous results reported the optimization induction conditions during batch and continuous culture of recombinant E. coli, and consequently fed-batch culture have received less attention....

Production of methane by Methanosarcina barkeri from H(2)-CO(2) was studied in fed-batch culture under phosphate-limiting conditions. A transition in the kinetics of methanogenesis from an exponentially increasing rate to a constant rate was due to depletion of phosphate from the medium. The period of exponentially increasing rate of methanogenesis was extended by increasing the initial concent...

Zeaxanthin is a xanthophyll pigment that is regarded as one of the best carotenoids for the prevention and treatment of degenerative diseases. In the worldwide natural products market, consumers prefer pigments that have been produced from biological sources. In this study, a Dunaliella tertiolecta strain that has 10-15% higher cellular zeaxanthin content than the parent strain (zea1), was obta...

BACKGROUND On-site cellulase production using locally available lignocellulosic biomass (LCB) is essential for cost-effective production of 2nd-generation biofuels. Cellulolytic enzymes (cellulases and hemicellulases) must be produced in fed-batch mode in order to obtain high productivity and yield. To date, the impact of the sugar composition of LCB hydrolysates on cellulolytic enzyme secretio...

This study discusses poly(3-hydroxybutyrate-co-4-hydroxybutyrate) that is produced by Delftia acidovorans bacteria in fed-batch cultures from various carbon sources. The experimentally determined optimal fed-batch culture conditions are as follows: pH: 7.0, incubation temperature: 26 8C, incubation time: 72 h, and concentration of carbon source: 10 g/L. The maximum 4HB unit composition of P(3HB...

The present study aimed at developing a strategy to improve the volumetric production of PHAs by Pseudomonas fluorescens S48 using waste frying oil (WFO) as the sole carbon source. For this purpose, several cultivations were set up to steadily improve nutrients supply to attain high cell density and high biopolymer productivity. The production of PHAs was examined in a 14 L bioreactor as one-st...

Fed-batch culture is often used in industry, and dissolved oxygen (DO) concentration control is important in fermentation process control. DO control is often applied by using feedback (FB) control strategy. But, feedforward-feedback (FFFB) control has the advantage in dealing with the time-varying characteristics resulting from cell growth during the fermentation process. Mathematical modeling...

When the thiol-oxidizing agent diamide was added to a batch culture of Streptococcus faecalis during exponential growth, the specific activity of inorganic pyrophosphatase (EC 3.6.1.1) decreased to the level observed in the stationary phase. The effect of diamide was completely reversed by reduced glutathione. Furthermore, the ratio of reduced to oxidized glutathione and the specific activity o...

β-Glucan is a cell wall component that is one of the most plentiful cell polysaccharides. Moreover, it has been found to have several beneficial effects on the immune system. In yeast, β-glucan is mainly contained in the yeast cell wall, and thus it is important to produce high levels of cell mass for the mass production of yeast β-glucan. Response surface methodology (RSM) offers a potential m...