The pH of the reaction mixture affects bio-production of lactic acid by loofa immobilized Rhizopus oryzae PTCC 5263

Baiza Mahdiar Roudsari¹ Azita Dejaloud² Farzaneh Vahabzadeh³

1) Amirkabir University of technology Email:
2) Amirkabir University of technology Email:
3) Amirkabir University of technology Email:

Publication : 3rd international conference of Science and Engineering(3icesconf.com)
Abstract :
Lactic acid production by Rhizopus oryzae PTCC 5263 was evaluated in the present study and the strain’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 maximum productivity was obtained during second 24 h of fermentation for immobilized cells (1.82 g/l.h) and final production and yield of lactic acid were 54.06g/l and 45.6%, respectively. Therefore, the immobilization of R. oryzae in loofa sponge can sustain stable morphology control in filamentous fungal fermentation and prevent the oxygen and nutrient limitations. Thus, cell immobilization via adsorption in the bare pieces of loofa sponge is a suitable technique in lactic acid production.
Keywords : Lactic acid; Rhizopus oryzae; Loofa sponge; Immobilization; Fermentation