Characteristics of L-lactic Acid Production byRhizopus oryzae mutant RL6041

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.

Key Words:

• Ions implantation
• L (+)-lactic acid
• Rhizopus oryzae
• fermentation

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