Research On Microbial Lipid Production From High Concentration Organic Wastewater As Culture Medium By Lipomyces Starkeyi

The research on high concentration organic wastewater treatment technology is one of research hotspot in the field of environmental science and engineering currently. If not be processed reasonably, emitted to environment directly, the wastewater will bring seriously negative effect on people’s normal life. Therefore, it is important to find an effective, potential and promising treatment method for the treatment of the wastewater.In this paper, four kinds of high concentration organic wastewater, including monosodium glutamate wastewater, beer wastewater, potato starch wastewater and soybean protein wastewater were usde as the fermentation medium, and Lipomyces Starkeyi was applied for the shake flask culture experiment. Using single factor test design, the influence factors of carbon source concentration and type, source of nitrogen concentration and types, cultivation time, dissoved oxygen, inoculumn size and initial pH on cell growth and lipid accumulation were discussed, and the oil fatty acid composition was analyzed by Gas Chromatography Mass Spectrometry (GS-MS). This method not only can reduce the cost of wastewater treatment, reduce the environmental pollution, realize the reuse of wastewater recycling and utilization, and benefit to environmental protection and sustainable development of society and economy, but also can provide reference and basis for microbial oil industrial fermentation production.The results of the study in this thesis are as follows:(1) Microbial treatment of the monosodium glutamate wastewater by Lipomyces Starkeyi to produce microbial lipid, the best conditions for lipid production were as follows:glucose concentration of80g/L, initial pH5.0,10%inoculumn size, cultivation time96h. Under this condition, the biomass production、lipid production、 lipid content、protein and COD removal rate reached up to4.61g/L、1.14g/L、24.73%、78.60%and74.96%, respectively. The main composition of fatty acid in the resultant lipid was analyzed by Gas Chromatography Mass Spectrometry, which showed:oleic acid (Cl8:1)35.85%, palmitic acid (Cl6:0)19.91%, palmitoleic acid (C16:1)17.65%, and myristic acid (C14:0)16.03%.(2) Using the beer wastewater as fermentation medium, the influence of carbon source type, nitrogen source type, initial pH value, inoculation size and cultivation time for cell growth and lipid accumulation was discussed. The result was:glucose as optimum carbon source,(NH4)2SO4as optimum nitrogen source, initial pH of about5.0, inoculation volume of25%, cultivation for4d, and a biomass of7.05g/L, a lipid production of0.39g/L and a lipid content of5.53%could be achieved.(3) Lipomyces Starkeyi was used as strain to treatment the potato starch wastewater. Through the shake flask culture, the optimum conditions of the carbon source type, glucose concentration, nitrogen source type,(NH4)2SO4concentration, inoculation quantity and cultivaton time were:120g/L of glucose concentration,30g/L of (NH4)2SO4concentration,10%inoculum size, and incubation time96h cultivated in a shaking flask at30℃. Under this condition, the cellular biomass and lipid content could reach2.59g/L and8.88%, respectively(4) The soybean protein processing wastewater with high organic materials was used as a fermentation medium to produce microbial lipid by Lipomyces Starkeyi Using the single factor test design and regulating the glucose and nitrogen source concentration, initial pH value, inoculation amount and pass oxygen, the results showed that the appropriate fermentation conditions were glucose concentration60g/L, NH4Cl concentration1.0g/L, pH7.0, inoculation size10%, dissolved oxygen90mL. Under these conditions, Lipomyces Starkeyi accumulated lipids up to7.74%, biomass yield of5.68g/L, and the corresponding lipid production reached0.44g/L.