Study of lactic acid fermentation by Lactobacillus amylovorus using cassava starch
2000
Sudip Kumar Rakshit | Guo Xuan | Wang Xiaodong(Asian Institute of Technology, Pathum Thani (Thailand).. Bioprocess Technology Program)
Lactobacillus amylovorus ATCC 33620 was used to study lactic acid production on cassava starch and other carbohydrate substrates. This strain was able to completely metabolize raw corn, rice and wheat starch to produce lactic acid, but only partially hydrolyzed cassava and potato starches. On a basal medium (with) yeast extract as the nitrogen source), pH and vitamin B had no significat effect on the growth of the strain. When peptone (1 percent) was added to the basal medium with cassava starch as substrate, lactic acid production increased from 4.72 g/l (42.5 percent conversion) to 7.72 g/l (70.2 percent conversion). This indicates that one or more components of the peptone might be the limiting factor for bacterial growth and production of lactic acid. The organism was able to utilize corn starch in basal medium with a lactic acid production of 10.05 g/l (90.5 percent conversion). This strain also poorly utilized glucose when yeast extract was the sole nitrogen source. A cheap nitrogen source, which could replace peptone as a source of growth stimulation, may be the economically feasible route for the direct fermentation of cassava starch to lactic acid.
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