Utilization of pine needles as bed material in solid state fermentation for production of lactic acid by Lactobacillus strains

Abstract

Pine needles, which are abundantly found as underexploited biomass in coniferous forests, are responsible for fire hazards and air pollution. Utilization of pine needles as bed material in lactic acid production with solid state fermentation (SSF) has been studied here. This investigation compared lactic acid production by pure strains of Lactobacilli, (1) L. delbrueckii(NCIM2025); (2) L. pentosus (NCIM 2912); (3) Lactobacillus sp.(NCIM 2734); (4) Lactobacillus sp. (NCIM2084); and a co-culture of the first two strains. The studies required 6 g per flask powdered dry pine needles as bed material, 2 g/L (inoculum), liquid production media based on pure glucose or whey substituted glucose, at 60, 80, and 120 g/L sugar levels, 37 oC, and an initial pH of 6.5. Co-culture attained a maximum lactic acid concentration of 45.10 g/L, followed by that of strain-1, 43.87 g/L and strain-4, 26.15 g/L, in 80 g/L pure glucose media. With 120g/L total sugar in whey-substituted media, the co-culture attained maximum lactic acid production of 44.88 g/L followed by that of strain-1, 43.67 g/L. The present experimental studies indicated better compatibility of pine needle bed with co-culture in solid state fermentation of lactic acid, which may prove to be an eco-friendly technology for utilization of biomass as well as minimizing fires in coniferous forests.