Studies On The Preparation Of Mannitol By Fermenting Broken-rice

Broken-rice is an accessory substance during rice processing,the nutrition of itis very rich.But the depth of further using is rather low all the time,the EconomicValue Added isn’t high.Mannitol is a kind of natural function polyol, the applicati-on of it is so wide in food,medicine,light industry and chemical industry.Broken-rice is rich in starch,it can be transformed to starch sugar by microbial fermentationfor product mannitol.So a new way for utilizing broken-rice was offered.The task had consisted of any aspects as follows:compositing mutagenesisbreeding of Lactobacillus fermentation which is stable and high yield;optimizingthe fermentation condition of high yield mutagenesis strains by single factor exper-iment and response surface experiment;optimization of seperation and purificationcraft of mannitol by broken-rice fermentation,preparation of mannitol finished pro-duct. The main results were as follows:(1) Under the suitable irradiation time,the Lactobacillus fermentation CICC-20660was irradiated by microwave,and mutagenesis strains LW16was received,LW16could produce19.18g/L mannitol after48h of fermentation.Then under thesuitable process time,LW16was disposed by ethyl sulfate,stable mutagenesis strainLS33was received,it produced22.56g/L mannitol after48h of fermentation,theconcentration of mannitol increased by20.3%than the original strain CICC-20660.(2) A number of influencing factors were optimized by single factorexperiment and response surface experiment,and the quadratic regression equationmodel of mannitol production was established.The best fermentation condition ofLS33producing mannitol was:75g/L fructose mass concentration,original pH6.9,42℃fermentation temperature,10%inoculums size,120r/min shaker speed. Theproductivity of mannitol was53.66%under this condition.It increased18.93%thanbefore45.12%.(3) The mannitol in broken-rice fermentation liquor was purified by ion-exchange column chromatography.The best condition of process was:30mL inputquantity,40℃elution temperature,2mL/min elution flow rate,20cm resin height.The yield of mannitol was95.28%at present.The class of broken-rice fermentationliquor was collected,evaporated ratoting,recrystallization,the mannitol crystalloid obtained was white acicular,homogeneous,no peculiar smell.The purity of mannitolwas above99%by analysis of High Performance Liquid Chromatography.