Optimization of L(+)-Lactic Acid Fermentation Without Neutralisation of Rhizopus Oryzae Mutant RK02 by Low-Energy Ion Implantation

摘要

In order to get an industrial strain which can yield a high concentration of lacticacid for ISPR (in situ product removal),the original strain Rhizopus oryzae RE3303 was mutatedby low-energy ion beam implantation.A mutant RK02 was screened,and the factors such asthe substrate concentration,nitrogen source concentration,inoculum size,seed age,aeration andtemperature that affect the production of lactic acid were studied in detail.Under optimal con-ditions,the maximum concentration of L(+)-lactic acid reached 34.85 g/L after 30 h shake-flaskcultivation without adding any neutralisation (5% Glucose added),which was a 146% increase inlactic acid production after ion implantation compared with the original strain.It was also shownthat RK02 can be used in ISPR to reduce the number of times of separation.