The studies on production of L lactic acid have been carried out in biotechnology laboratory, by solid state fermentation. The experiments on groundnut shells are carried out, as substrate which is the cheapest raw material available in India. The culture Lactobacillus delbrueckii NCIM 2025 was obtained from Natural Culture Collection Centre, NCL Pune. At lower temperatures i.e., 37�C and 40�C the lactic acid production was 17 g/l and 23.0 g/l respectively. Lactic acid was estimated by A. C. Kimberley Taylor method. The ground nut shells were treated prior to conducting the experimental investigation. The mutant cells were tested for its stability on 0.6% Allyl alcohol, which was a selection agent. Mutants were generated by exposing to UV radiations, with different exposure times and stability was tested. The results were encouraging and the lactic acid produced was about 23 g/l at temperature of 42�C. The pH optimum was found to be about 5.2 and inoculum size was found to be 3 ml. The present study refocused on accumulation of lactic acid by using ground nut shells having lingo cellulosic material.