Lactic acid production by Rhizopus oryzae PTCC 5263 was evaluated in the present study and the strain rsquo;s ability in production of this organic acid was carried out at various pH ranges of the culture media. Lactic acid production was optimized upon the fermentation being controlled at pH 4.5 by adding calcium carbonate slurry and maximum lactic acid concentration was 41 g/l. Additionally, the production of lactic acid by loofa immobilized R. oryzae was compared with free cells and the ...