Activity against plant pathogenic fungi of Lactobacillus plantarum IMAU10014 isolated from Xinjiang koumiss in China

Thirty-five of the 77 colonies of lactic acid bacteria isolated from koumiss showed antifungal activity against Botrytis cinerea, when tested by the Poison Food Technique. Of these, the most promising isolate having a broad spectrum of antifungal activity, including against Botrytis cinerea, Alternaria solani, Phytophthora drechsleri Tucker, Fusarium oxysporum and Glomerella cingulata, was identified as Lactobacillus plantarum IMAU10014. The effect of pH, temperature and protease on the antifungal activity of L. plantarum IMAU10014 was determined. The activity substance was heat stable. The maximum antifungal activity was observed at pH 4.0. When the supernatant was adjusted to pH 8.0, the activity was lost irreversibly. However, after enzymatic treatment of supernatant with trypsin, neutral protease and proteinase K, loss of part of the antifungal activity was observed which indicated there are other substances in addition to the proteinaceous substance with the antifungal activity.