EFFECTS OF NUTRITIONAL FACTORS ON GROWTH OF LACTOBACILLUS-FERMENTUM MIXED WITH SACCHAROMYCES-CEREVISIAE IN ALCOHOLIC FERMENTATION

The growth of Lactobacillus fermentum was studied in mixed culture wit h Saccharomyces cerevisiae during alcoholic fermentation of high test molasses (HTM). Yeast extract or a group of 17 amino acids caused a st rong and fast decrease in yeast viability due to the strong increase o f acidity produced by bacteria. Pure culture of Lactobacillus fermentu m in dry sugar cane broth confirmed amino acids as the main nutrients needed to stimulate the growth of bacterial contaminant during alcohol ic fermentation. The absence of L. fermentum growth was obtained when leucine: isoleucine or valine were not added to the medium. Phenylalan ine, alanine, glutamic acid, cystine, proline, histidine, arginine, th reonine, tryptophane, serine and methionine inhibited the bacterial gr owth at least in one of the cultures of L. fermentum tested.