The Research Of Pretreatment Of Kitchen Garbage And The Indigenous Bacteria Take Use Of The Hydrolysis Liquid To Ferment To Produce Microbial Oil

Due to its renewability and environmental protection effect,biodiesel is called “green energy”,and has vast prospects.The traditional raw material of biodiesel are vegetable oil and animal fats,but microbial oil as material has obvious advantages of the vegetable oil and animal fats.The proliferation of microorganisms fast,the growth cycle is short,and the material which microorganisms need is abundant and cheap.Besides,the needed labor force in production process not being affected by the season or climate etc,is less than that of the animal and vegetable oil.So microbial oil is an ideal raw material for biodiesel.The purpose of this paper was to study that the oleaginous microorganisms ferment to produce oil with hydrolysis liquid of kitchen garbage which was through pretreating and composite enzyme treatment,Saccharomyces cerevisiae As2.516 took hydrolysis liquid of kitchen garbage as medium to conduct passaging and domesticated culture,and the oleaginous microorganisms separated and purified from soil enriched with oil and sugar was mutated with ultraviolet radiation,so as to obtain higher oil yield.The results were as follows:1)Different methods of pretreatment(hydrothermal pretreatment,acid-alkali pretreatment,Oxygen pretreatment)had apparent effect on the degradation of organic matter.These methods could improve the percentage of reducing sugar and the content of amino acid nitrogen.The optimum conditions of four pretreatment methods were as follows: hydrothermal pretreatment for 2h under 60?,when the initial pH was 7,effect of acid pretreatment(the initial pH was 2 to 7)was best and the initial pH was 8 for the alkali pretreatment(the initial pH is 7 to 11).It gave a comprehensive conclusion that raw liquor by acid-alkali pretreatment can get the best effect when the pH of raw liquor was 8,and the anoxic condition was more suitable for the degradation of organics.Considering the three pretreatment methods,it concluded five comprehensive methods to pretreatment.among these five methods,it got a optimum condition that is to pretreatment for 24 h under indoor temperature,while it was anoxic and the pH was 8.By pretreatment,the complex enzyme preparation could efficiently conduct hydrolysis for macromolecular organic matter of kitchen garbage.Then the micromolecular matter can be utilized by the microorganism.To get the best hydrolysis effect,the dosage of complex enzyme preparation was as follows: In each gram of raw material,there were 16 vitalities of amylase and 320 vitalities of glucoamylase,and the content of protease and cellulose were 50 vitalities respectively.In addition,enzyme hydrolysis needed a appropriate condition,and different time,temperature and pH had influence on the effect of hydrolysis.In this experiment,when the initial pH at 7,hydrolyzing for 2h under 55?,the result was the best.2)Extracted the microbial oil with methods as follows: First screening with plate,SBB staining,the second screening with shake flask fermentation,and acidified thermal method.Finally,the two strains with high oil content were obtained from the soil samples which contain rich oil and carbohydrate.Identificated with molecular biology and morphology,the bacterial strain B was Burkholderiatropica and the strain D was Chaetomium globosum.The experiment result showed that the strain D can produce the highest microbial oil by making use of the kitchen waste and fermenting,so we proceed ultraviolet mutation on it.And the oil production content and yield was 31.27% and 6.117g/L,respectly,and comparing the condition without mutagenesis increase by 5.16% and 1.128 g/L.Then we conducted continuous sucultural activation on mutant strains,and find that its oil production content and yield was stable at 29.86% to 33.55%,5.832g/L to 6.226g/L,respectively,which stated that the srtain owns a quite stable heritability.3)In the hydrolysis liquid of kitchen garbage,we proceeded passaged habituated culture on the Saccharomyces cerevisiae.The study found,among the six generations,the oil production content and yield reached to the top when it came to the last generation,which was 29.52% and 8.604g/L,respectly.