Optimization of malolactic fermentation parameters with isolated and characterized lactic acid bacteria associated with grape berries

Abstract

A total of 21 microorganisms were isolated from grape berries’ of Punjab MACS purple and H-144. Qualitative analysis (growth on YNB media) of the nine bacterial isolates lead to screening of PII and HIII for malic acid deacidification. Quantitative estimation showed that PII isolate (59.0%) had higher malic acid deacidification rate than HIII (49.7%) compared to the standard L. oenos culture that had 67% malic acid deacidification efficiency. Molecular identification indicated that the PII isolate belongs to Lactobacillus sp. having 99% similarity with Lactobacillus plantarum subsp. argentoratensis AJ640078 and 98% similarity with Lactobacillus plantarum CP010528. Post-ethanolic malolactic fermentation by PII at the rate of 7.1% (v/v) inoculum size with 243.2 mg/L YNB supplementation lead to 58.7% and 60.0% deacidification of malic acid to lactic acid in 12 days among grape juice resulting in wine production with desirable malic acid contents. Practical applications The study represents the effect of Malolactic fermentation on grape wines resulting in reduced malic acid content having more smooth and buttery flavor in the final quality wine. Malolactic bacteria isolated from the grape berries itself have a good potential to carry out malolactic fermentation and performs at par with the commercial strains that can be explored and commercialized further for the industrial use.