DELIGNIFICATION OF CORN COB FOR THE SYNTHESIS OF LACTIC ACID
Petroleum-based polymers are associated with environmental and sustainability issues such as environmental pollution and global warming. In view of these issues, corn cob was pretreated for the synthesis of lactic acid. Lactic acid is the base material for poly lactic acid production. The corn cob (Zea mays) which contains 79.73% holocellulose (cellulose+hemicellulose) and 16.24% lignin was subjected to oxalic acid pretreatment in order to remove lignin. With the aid of Central Composite Design (CCD) on Design-Expert 6.0.6 Software, the pretreatment was optimized at a temperature range of 25-120 oC and a time range of 30-60 min. Optimization studies revealed that the optimum temperature and time for oxalic acid treatment was 25 oC/30 min, holocellulose content improved from 79.73% to 85.565% and expectedly lignin content reduced from 16.24% to 9.91%. Fermentation with Bacillus coagulans at a temperature of 50 oC, a pH of 6.0 and a time of 48 hr produced lactic acid with a yield of 82%. This implies that oxalic acid pretreatment of corn cob is effective for the synthesis of lactic acid.