L-lactic acid production by Rhizopus oryzae MBG-10 using starch-rich waste loquat kernels as substrate

The objective of this work was to perform production of L-lactic acid from starch-rich waste loquat kernels by newly isolated Rhizopus oryzae MBG-10 fungus. Loquat kernel flour (LKF) was used as substrate (mainly as carbon source). The most favorable conditions for L-lactic acid production were LKF concentration of 80g/L, CaCO3 concentration of 20g/L, ammonium sulfate concentration of 3g/L and incubation time of 108h. Under these conditions, L-lactic acid and biomass concentrations were 45.4 and 8.2g/L, respectively, and -amylase activity was 81.6U/mL. No significant pH changes were observed in the medium thanks to the buffering capacity of LKF. L-lactic acid could be produced in a single-stage from starch-rich LKF without prior saccharification by the fungus with high amylolytic enzyme activity. This is the first report on use of waste loquat kernels as a lactic acid production substrate.