Batches, strategy

R. D. Kiss and G. N. Stephanopolous, Metabolic activity control of the L-lysine fermentation by restrained growth fed-batch strategies, Biotechnol Prog. 7, 501-509 (1991). 

Chee F, Wong D, Tin Kam Wong K, Tang Goh L, Kiat Heng C, Gek Sim Yap M (2005), Impact of dynamic online fed-batch strategies on metabolism, productivity and N-glycosylation quality in CHO cell cultures, Biotechnol. Bioeng. 89 164-177. 

Most recently, this group applied the metagenome screening strategy for fhe identification of improved DERA enzymes [75]. More than 15 DERA enzymes were discovered, of which one was used to optimize the process mentioned (Scheme 4.17E) on a 100 g scale. Using a fed-batch strategy, which is necessary because of substrate inhibition, Burk et al. obtained a final product concentration (16) of 93 g I. (>99.5% ee, de 96.6%). Concomitantly, the amount of enzyme was reduced to 2% (wt/wt). 

One approach to implementing a fed-batch strategy is to feed cultures with medium concentrates. This can offer a rapid approach to increasing productivity, and can also be relatively simple to implement [17, 74]. Using GS-NSO cells producing an antibody, Bibila et al. [17] fed cultures with lOx basal medium concentrates (Iscove s Modified Dulbecco s medium) to increase productivity. Sodium chloride, potassium chloride and sodium bicarbonate were omitted from the medium concentrates in order to minimize the increases in osmo-larity caused by feeding. In their system, feeding basal medium concentrates did not result in an increase in the maximum viable cell concentration or the IVC. However, the final antibody concentration was increased 1.9-fold as a result of an increase in the specific production rate. 

A pH-stat fed-batch strategy was applied for the culture of transformant Ralstonia eutropha REZ coexpressing the phbC and zwf genes. It was cultivated in a minimal medium followed by feeding 10 g/1 of fructose and valerate to maintain a pH level of 7.0. This strategy resulted in the production of a 60.1% poly(3HB-co-3HV) copolymer and cell mass of 14 g/1. The 3HV monomer composition reached 71.9 mol% [18]. 

Zakaria and co-workers [28] reported the use of Comamonas sp. FBI 72 for the fed-batch production of copolymer poly(3HB-co-3HV) using a mixed organic acids treated palm oil mill effluent (POME) in a 2 1 bioreactor. A PHA content of 59 wt% and 3HV monomer composition of 21 mol% was obtained when the two-stage cultivation method was used. This method involves growing cells in a nutrient-rich medium for about 12 h, followed by inoculation of the production medium and supply of concentrated organic acids from treated POME using the fed-batch strategy. 

Nie ZK, Ji XJ, Huang H, Du J, Li ZY, Qu L, Zhang Q, Ouyang PK. (2011). An effective and simplified fed-batch strategy for improved 2,3-butanediol production by Klebsiella oxytoca. Appl Biochem Biotechnol, 163, 946-953. 

Yu Z, Du G, Zhou J, Chen J. Enhanced a-ketoglutaric acid production in Yarrowia /ipo/yfiVa WSH-Z06 by an improved integrated fed-batch strategy. BioresourTechnol 2012 114 597-602. 

Liu et al. reported PHB production from molasses by recombinant E. coli.Ehe fermentation with molasses was economically viable when compared to that of glucose. The PHB content and productivity were 80% w/w and 1 g/L/h, respectively.The study revealed that molasses concentration had a significant effect on PHB synthesis and cell growth. A fed-batch strategy was adopted to overcome substrate inhibition as well as to improve cell growth and PHB production. 

Product tolerant mutants of C. butyricum DSM 5431 were isolated by Abbad-Andaloussi et al. (1995). Besides showing product tolerance, these mutants also yielded a higher biomass in fermentation. To further explore the use of these mutants, a fed-batch strategy was used which coupled the feeding of glycerol and ammonium to alkali consumption. A mixture of glycerol. 

Kitcha, S., Cheirsilp, B., 2013. Enhancing lipid production from crude glycerol by newly isolated oleaginous yeasts strain selection, process optimization and fed-batch strategy. Bioenergy Research 6, 300—310. 

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