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The physiology of lactate production by Lactobacillus delbreuckii in a chemostat with cell recycle
Author(s) -
Major Nicolas C.,
Bull Alan T.
Publication year - 1989
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260340503
Subject(s) - industrial fermentation , chemostat , fermentation , chemistry , lactate dehydrogenase , food science , bioreactor , biomass (ecology) , biochemistry , yield (engineering) , ultrafiltration (renal) , chromatography , pulp and paper industry , biology , bacteria , enzyme , organic chemistry , materials science , agronomy , metallurgy , genetics , engineering
The physiology of lactate production by Lactobacillus delbreuckii NRRL B‐445 in a continuous fermenter with partial cell recycle has been studied and compared with that observed in a conventional chemostat. Partial cell recycle was achieved using a hollow‐fiber ultrafiltration cartridge. The biomass growth yield was reduced in the recycle fermenter while culture viability and the cellular content of polysaccharide, protein, carbon, and nitrogen remained constant, suggesting an enlarged specific rate of glucose consumption for nonanabolic (e.g., maintenance) functions. The volumetric productivity of lactate was enhanced in the recycle fermenter due to the complete utilization of glucose. The yield of lactate from biomass and the molar product ratio, lactate: ethanol plus acetate, decreased with increasing recycle ratio. Enhanced formation of ethanol and acetate occurred in the recycle fermenter although lactate remained the major product. The change in product profile was due to glucose limitation. The specific activity of lactate dehydrogenase remained constant during recycle fermentation. These physiological observations have implications for the future application of cell recycle to production processes.