Abstract
A high-yield mutant strain Rhizopus oryzae RL6041 induced by ions implantation was used in the present study. L (+)-lactic acid was generated by RL6041 grown on liquefied corn starch as a substrate. With optimal conditions (Liquefied corn starch 150g/L, (NH4)2SO4 2.0g/L, MgSO4·7H2O 1.0g/L, ZnSO4·7H2O 2g/L, KH2PO4 0.2g/L, CaCO3 8%, medium size 20/250Ml, seed age 6h, fermentation temperature 38° C), the yield of L (+)-lactic acid in shake-flask reached 133∼136g/L after 36h, indicating that the conversion rate was as high as 88%∼91%, and the productivity was 3.75g/L·h. There was almost a 70% increase in lactic acid production compared with the original strain RE3303.
Notes
Shi, Q.Sh., Wu, S.G. (2003). Breeding study in industrial microorganism:78 Science publishing house. Beijing (In Chinese)
Yu, Z.L. (1998). Introduction to ion beam biotechnology (in Chinese); Anhui scientific and technical publishing house