Isolation and identification of a low-pH, lactic acid and succinic acid tolerant strain

Abstract:

[Objective] The aim of this study was to screen a low pH, lactic acid and succinic acid tolerant strain from the artificial acidic ecosystem. [Methods] A strain resistant to low pH, lactic acid and succinic acid was isolated from the artificial acidic ecosystem by acidic plates. We identified the strain by morphological and physiological traits, combined with 18S rDNA gene sequence and phylogenetic trees. [Results] A strain named WJ-2 with low pH, lactic acid and succinic acid tolerance was obtained and identified as Saccharomyces cerevisiae. Its optimal growth temperature was 30 °C, and it could survive in acidic plate at pH 2.5 and grow in the plate with a lactic acid concentration of 9% (w/v). WJ-2 also showed a succinic acid tolerance (8% succinic acid, w/v). WJ-2 also displayed a relative neutral intracellular pH when being challenged at pH 2.5, 9% lactic acid and 8% succinic acid. [Conclusion] Artificial ecosystem is a good alternative to screen strain with specific characteristics.