Lipid Production With Hemicellulosic Hydrolysate By Rhodotorula Glutin As2.107

At present, the world are facing with the serious energy and enviromental problem .With the problem of global energy shortage and environmental deterioration become more and more seriously, people are exploring the renewable energy to substitute the fossil fuel. Biodesel is such a kind of clean and renewable energy with great development potential. The raw materials of biodiesel are vegetable oil and waste oil at present . However, the high material price of vegetable oil and waste oil led to the high production cost of biodiesel production. So develop cheep materials are very important for the biodiesel industrialization. Some studies find that many microbe have a great deal of lipid in the body and can co-fermentate glucose and xylose simultaneously, so production of lipid material by microbial fermentation using hemicellulosic hydrolysate can provide a wide range and cheap raw materials for biodiesel.First of all ,the batch and feed-batch fermentation in shaker and fermentor by fermentation of glucose with rhodotorula gutini As2.107 was investigated respectively.The experimental results showed that: the yeast growth will not be inhibited by glucose when the sugar concentration under 100 g/L, and the optimum initial glucose concentration is about 50g/L, the biomass of using organic nitrogen is higer than inorganic nitrogen but the lipid content of later is higher than the former, because of offering a higher kalium and lower natrium for the cell, using potassium nitrate under 4g/L as nitrogen source will promote lipids accumulation, the biomass and lipid can reach 17.7g/L and 6.4g/L while growing in 1L fermentor in which the optium operation is that ventilation was 1vvm , pH is 6 and stirrer speed was 550 rpm.The feed-batch fermentation in shaker by fermentation of glucose with rhodotorula gutini As2.107 was investigated. The biomass and lipid can reach 16.8g/L and 9.1g/L while adding glucose(14 g/L) in the medium at 48h during fermentation.The batch fermentation in shaker by fermentation of xylose with rhodotorula gutini As2.107 was investigated. The effects of fermentation operation parameters on fermentation process and lipid synthesize were discussed. The results showed that: the yeast growth will be inhibited by the high concentration of xylose, both of the biomass and content of lipid were maximum when xylose concentration is about 35g/L, KNO3 and yeast were used as nitrogen source, the yeast concentration is about 4g/L ,the ratio of carbon and nitrogen was 55, inoculation amount was 15% and the concentration of KH2PO4 is 6g/L.The batch fermentation in shaker by cofermentation of glucose and xylose with rhodotorula gutini As2.107 was investigated. The results showed that: both of the biomass and content of lipid were maximum when the ratio of xylose and glucose is 2.5, the total concentration of sugar is about 50g/L, KNO3 and yeast were used as a nitrogen source, the yeast concentration is about 4g/L ,the ratio of carbon and nitrogen was 55, When grown on mixed sugar containing glucose (15g/L) and xylose (35g/L) under feed-batch fermentation which adding 15~25g/L sugar (ratio of xylose and glucose is 2.5) 72~84h after beginning fermentation, biomass and lipid content were19.5 g/L and 59.5% respectively.The influence of furfural and acetic acid on Rhodotorula glutin As2.107 growth was investigated. The yeast will stop growth when their concentrations exceeded 2 g/L. When grown on bagasse and corncob, biomass were15.1g/L and 13.7g/L,lipid content were 32.5% and 29.2%. So the hemicellulosic hydrolysate can be used as raw material to produce microbial lipid when removal of toxin from it. The lipid produced by fermentation which using lignocellulosic hydrolysate as raw material is also can be used to prepare of biodiesel.