A PROCESS FOR THE PRODUCTION OF LACTIC ACID FROM CORN MEAL BY SIMULTANEOUS STARCH SACCHARIFICATION AND LACTIC ACID FERMENTATION USING DRIED PLANT BIOMASS OF TINOSPORA CORDIFOLIA AS THE SOURCE OF SACCHARIFYING ENZYMES

摘要

The present invention relates to a process for the production of lactic acid from corn meal by simultaneous starch saccharification and lactic acid fermentation using dried plant biomass of Tinospora cordifolia as the source of sacchrifying enzymes. Lactic acid, , has applications in the food, pharmaceutical, chemical, textile, cosmetic, and leather industries and as is the raw material for the production of poly lactic acid (PLA) now extensively used for manufacture of biodegradable plastic. PLA production essentially requires pure optical isomers of lactic acid which is only produced by fermentation processes. Different homofermentative lactobacilli are used for the commercial production of lactic acid which produces more than 85% lactic acid from glucose. Lactic acid production from cereal starch is more economic than from glucose, provided cereal starches (mainly corn) are easily hydrolyzed into glucose by multiple amylolytic enzymes, obtained from microbial sources. The present technology to produce fermentable sugar from cereal starch includes thermostable a-amylase or starch liquefying enzyme which catalyzes hydrolysis of internal α-1,4 glycosidic linkages of starch into dextrin. Next glucoamylase catalyses hydrolysis α -1, 4 and α -1, 6 glycosidic bonds of dextrins into glucose as final product. Commercially it is known as Two enzyme cold process. Presently saccharification steps and fermentation steps are carried out in separate vessels under different conditions. The ideal situation for the production of lactic acid from starch may be simultaneous single step saccharification of starch into glucose by a single enzyme composition and fermentation of the glucose into lactic acid under the same reaction conditions. The regular withdrawal of glucose from the saccharification equilibrium by the lactic acid bacteria is likely to shift hydrolysis equilibrium to the stoichiometric conversion of starch into glucose. In 2002, Sengupta et al first reported huge extracellular a-amylase by Tinospora cordifolia . The amylase is a thiol protein which hydrolyzed both amylose and amylopectin with the production of disaccharide as major end product. A number of disaccharidases like maltase, isomaltase, sucrase lactase etc were found to be present in appreciable amounts along with the amylase in the crude enzyme preparation. The present invention provides a process , with 3 examples, for the production of lactic acid from corn meal which includes gelatinization of corn meal at 100°C at a pH of 4.5 to 7.0, mixing with 0.5 to 1.5 % (w/w) dry Tinospora cordifolia stem powder incubating the mixture at temperature 45-50 °C for 48 hours followed by adding 5-10% (v/v) 48 hours grown Lactobacillus sp. CaCO3 powder and yeast extract , further incubating at 30-37 °C for 96 -120 hours , separating the liquid, acidifying the filtrate by H2SO4 and collecting the filtrate as a solution of lactic acid. Advantages (11) of the unique single step process for lactic acid production from corn meal using a unique saccharifying biocatalyst have been indicated and the patent submitted 10 claims.