L- lactic acid is an important edible organic acid, the requirement is next to the citric acid. It has biological activity, easy to be absorbed to human body and the energy transformation is six times than that of glucose, it is the best additives to sport beverage. L-lactic acid takes starch as its material, it is made by microbiological fermentation. The technology adopts enzyme converted sugar, fermentation with rhizopus, extraction with membrane filtration culture method and triple-effect concentration. Lactic acid is mainly applied in food industry which takes the half of requirement, then it is used in plastic, emulsion, medicine and cosmetic. In addition, L-lactic acid can also be used in polylactic acid ( PLA ) production which are containers package of one way box and cup, for PLA degradation to high molecular material to control white contamination. It is estimated that the requirement on the market reach to billion pound/year in the coming ten years. The requirement in our country is 1000T/year now.
The study on L-lactic acid fermentation technology began in 1992, which was one of provincial key technologies. The strain LQR-073 for producing -lactic acid was induced and cultivated, its physiological activity was explored and fermentation condition had been determined, the acid -producing rate reached to 12%. Using the advantages of esterification and direct extraction, a simple extraction method-solvent extraction was se up. The solvent was easy recovery and was better to remove residual sugar and miscellaneous acids. The extraction rate was over 76% and the purity reached to 97%. The technology was identified by Shandong Science & Technology Department in 2002 and considered to be taken the lead level in the country.