Efficient production of lactic acid from sucrose and corncob hydrolysate by a newly isolated Rhizopus oryzae GY18

Abstract

The aim of this study is to investigate production of L-lactic acid from sucrose and corncob hydrolysate by the newly isolated R. oryzae GY18. R. oryzae GY18 was capable of utilizing sucrose as a sole source, producing 97.5 g l(-1) L-lactic acid from 120 g l(-1) sucrose. In addition, the strain was also efficiently able to utilize glucose and/or xylose to produce high yields of L-lactic acid. It was capable of producing up to 115 and 54.2 g l(-1) lactic acid with yields of up to 0.81 g g(-1) glucose and 0.90 g g(-1) xylose, respectively. Corncob hydrolysates obtained by dilute acid hydrolysis and enzymatic hydrolysis of the cellulose-enriched residue were used for lactic acid production by R. oryzae GY18. A yield of 355 g lactic acid per kg corncobs was obtained after 72 h incubation. Therefore, sucrose and corncobs could serve as potential sources of raw materials for efficient production of lactic acid by R. oryzae GY18.