Effective Production of Lactic Acid by a Newly Isolated Alkaliphilic Psychrobacter maritimus BoMAir 5 Strain

Abstract

The contamination risk during lactic acid production is one of the challenges to be overcome for effective fermentation because most reported lactic acid bacteria are neutrophilic strains. Therefore, in this study, a newly isolated alkaliphilic lactic acid bacterium was selected among several isolates obtained from natural sources. This isolate was identified as Psychrobacter maritimus BoMAir 5 using morphological, biochemical fermentation tests and16S rRNA gene sequencing. The strain exhibited homo lactic acid fermentation from glucose at pH 9.0. It also showed broad sugars utilization especially those derived from lignocellulosic biomasses. Cultural and nutritional conditions were optimized for efficient lactic acid fermentation. Lactic acid concentration of 140.8g/l with yield of 0.94g/g of consumed glucose was obtained using multi-pulse Fed batch fermentation system with pH controlled at 9.0 and 40°C. For biotechnological application, Psychrobacter maritimus BoMAir 5 represents a potential strain for high lactic acid production under conditions that limit the contamination risk of fermentation.