ISOLATION AND SELECTION OF LACTIC ACID BACTERIA AND APPLICATION IN FERMENTION OF MUSHROOM (Volveriella volvacea)

Abstract

This study was conducted to isolate lactic acid bacterial strains and tested the production of fermented Volvariella volvacea mushroom. Lactic acid bacterial strains were isolated and tested for fermentation ability in MRS broth medium as well as screened for lactic acid fermentation of V. volvacea mushroom. Fermentation conditions were conducted with different initial cell concentrations (10³, 10⁵, 10⁷cells/g) and fermentation temperatures (30 °C, 37 °C and environmental temperature 28-32 °C). As a result, 20 bacterial strains were isolated from 6 samples of Nem chua (Vietnamese fermented pork roll). These bacterial strains are Gram-positive, rod-shaped, non-spore-forming, and nonmobile. Among these bacterial strains, 10 strains had good fermentation ability in MRS broth supplemented with 20 g/L of D-glucose including TX61, HCGT31, HK162, L54, L7, HK221, L39, HCM2, TX3, and L30 with the lactic acid concentrations of 10.5-21.0 g/L. The HCM2 strain, identified as Lactobacillus plantarum, produced the highest lactic acid concentration (14.3 g/L) when fermented of V. volvacea mushroom. The suitable conditions for fermentation were determined at 37 °C with the initial inoculum at 10⁷ cells/g in 24 hours.