The Research On The Saccharification And Simultaneous Saccharification And Fermentation With Corn Stover To Produce Nisin

Cellulose is the most abundant renewable natural biological resource, and theproduction of biobased products and bioenergy from less costly renewablelignocellulosic materials is important for the sustainable development of humanbeings. In China, corn straw residue is the most voluminous. It is reported that sixmillion tons would be produced in China. Such a substrate has gained great attentiondue to its potential to produce valuable products such as lactic acid and ethanol. Thisarticle is that improving the conversion rate of cellulose of corn stover to glucose andused of simultaneous saccharification and fermentation of hydrolyzate to producenisin and lactic acid.Lignocellulosic biomass is converted to glucose and xylan efficiency is animportant factor in the impact of simultaneous saccharification and fermentationprocess. Standard method for the determination of IUPAC cellulose enzyme activityof cellulase system overall saccharifying ability, through the filter paper as thesubstrate are generated glucose after cellulase hydrolysis of, the enzyme reaction withfilter paper after using3ml DNS chromogenic reaction, the total system is4.5ml. Foroptimize a method that is more accurate for the parallel analyses of large samplenumbers of cellulases, We developed the60-μl reactive format method to determinethe activities by finding the enzyme dilution out that would produce exactly2.0mgglucose equivalents of reducing sugar. In our study,60-μl format method comparedwith the IUPAC method by determining activities of seven kinds of cellulase derivedfrom different manufacturers respectively. It showed that the60-μl format FPA werenot significantly different from the results measured with the IUPAC method. And ithad high accuracy and reproducibility.In this study，cellulase is mixed with other substances in order to improve theglucan-to-glucose conversion. Studied by single factor tests that effects of cellulase,β-glucosidase、xylanase、pectinase、sodium thiosulfate、tween-80、PEG-6000、sodiumthiosulfate and bovine serum albumin for glucan-to-glucose conversion, the resultsshow that cellulose hydrolysis rate increases with increasing concentration of cellulase in the range of5~35FPU/g cellulase concentration and the optimumconcentration respectively was300μg/g、20μg/g、170μg/g、1.7μl/g、0.105%、0.75mg/ml、1mg/ml.Response Surface Methodology (RSM), enabled production ofan optimally supplemented enzyme complex. It shows that the maximum increasingyield was45.8%at377μg/g cellulose Novozyme188,171μg/g cellulose pectinaseand1mg/ml sodium thiosulphate.Nisin is valuable industrial chemical used as an acidulant preservative in foodindustry and other numerous applications. It can be produced by Lactococcus lactisfermentation. On the basis of above studies, simultaneous saccharification andfermentation by Lactococcus lactis subsp.lactisuesd simple sugars by enzymecomplexes hydrolysis of the pretreated corn stover. This study explores the aerobicand anaerobic simultaneous saccharification and fermentation by Lactococcus lactissubsp.lactis, and explore the effects of initial pH and substrate concentration of nisinand lactic acid production. The results show that when fermented under aerobic, nisinproduction reached the maximum5580IU/ml at24h; Under anaerobic conditions,nisin production reached a maximum5188IU/ml at the same time. Also founded thatthe formation of nisin was highest when substrate was4%and pH5.5in SSF.