Fermentation Of L-lactic Acid With Rhizopus Oryzae Cell

Microorganism cell with good adaptation to environment and reproductive capacity, synthesize some metabolites needed .It is of great significance that how to solve questions on grain,energy and environment using the metabolic control of microorganism cell. L-lactic acid, the raw material of biodegradable PLA which being increasingly used as biomaterials, attracted much attention.The basic conditions of metabolic control fermentation of rhizopus oryzae were studied to make true the continuous process and enlargement of production of lactic aid.The L-lactic acid production by immobilized Rhizopus oryzae in calcium alginate beads and vinylon were investigated with starch as carbon source which was using widely. Results indicated that immobilized cells in calcium alginate beads were easily to soft and break, and immobilized cells in PVA meet the need of continuous process. The addition of carrier,time ect on fermentation of production by Rhizopus oryzae in PVA was also investigated.Botanic cellulose, a kind of plenty cheap and reproducible resource, was used as material for the production of L-lactic acid with solid fermentation. Steam explosion was used on the pretreatment thought the comparison to many pretreatment methods for component separation on cellulose.As hydrolysis of cellulose carried with cellulase, results indicated thattime on enzymatic hydrolysis It was indicated that under the condition of substrate concentration is 4%, enzyme concentration is 2% ,temperature at 50℃, hydrolysis period about 60 hours and pH value is 4. 8. For the mineral salts added for the fermentation of lactic acid with Rhizopus oryzae, some are inhibited and the others are activated on the cellulase activity.For the difference between cellulase and growth temperature of Rhizopus oryzae, Simultaneous saccharification and fermentation changed was used for the production of L-lactic acid. 48.8mL citrate buffer and 2g cellulose after pretreated putted in 250mL triangle-bottle, as well as KH₂PO₄ 0.3g/L;MgSO₄ .7H₂O 0.25g/L;ZnSO₄ .7H₂O 0.08g/L,, sterilized with 121℃for 20min,enzymatic hydrolysis carried with 1.2mL cellulase on 50℃for 18h.Then after inoculation of Rhizopus oryzae, 1g CaCO₃ was putted utile fermentation ,which sustained for 5d with 52.7%,started for 10h.