Conversion Of Vineyard Winter Prunings Into Microbial Lipids By The Oleaginous Yeast Cryptococcus Curvatus

Vineyard Winter Prunings(VWPs)are organic farm waste,the main component of which is lignocellulose,consisting of lignin,cellulose,hemicellulose,moisture,ash,protein and minerals.The differences in VWPs composition are related to the variety,age and growing environment.VWPs are corrosion-resistant,and discarding them in the field or burning them can cause environmental pollution and waste of resources.Alkali and methanol pretreatment(AMP)can effectively break the stubborn structure of VWPs,remove lignin,protect cellulose and hemicellulose in VWPs from loss,and greatly improve the enzymatic hydrolysis efficiency.Cellulase hydrolyzes carbon sources from VWPs into sugar solutions.Cryptococcus curvature converts hydrolysate into high-value microbial oils.Microbial lipids contain unsaturated fatty acids and can be used in food,medicine and chemical industry.It is an excellent material for the preparation of biodiesel and biological lubrication.The research results of we were as follows:(1)The components of the VWPs of Cabernet Sauvignon were analyzed.It was mainly composed of cellulose,hemicellulose,lignin,moisture,and ash.Optimize the pretreatment conditions,and determine the four factors of pretreatment temperature,time,solid-liquid load and Na OH concentration by comparing the main components such as lignin,cellulose and hemicellulose in VWPs before and after pretreatment,calculate the solids recovery of VWPs after pretreatment.After pretreatment,the available reducing sugar was 0.73 g/g,and the sugar recovery rate reached 93%.(2)To explore the effect of cellulase loading and add cellulase in batches on saccharification efficiency:Under the condition that the enzyme addition amount was 12.5and the enzymatic hydrolysis was 72 h,the concentration of reducing sugars could reach72.6 g/L.The addition of cellulase in batches did not significantly improve the saccharification efficiency.After two rounds of enzymatic hydrolysis,90.6% of the available sugars were released.(3)Improve the efficiency of oil production by C.curvatus using VWPs hydrolysates by optimizing the C/N ratio and TRS.When the C/N ratio was 160 and the reducing sugar concentration was 40 g/L,7.4 g/L of lipid was obtaine and the content of bacterial body oil reached up to 60%.The ratio of reducing sugars to oil reaches 0.185.In order to simplify the conversion of VWPs into microbial oil,Improve the efficiency of oil production by C.curvatus from carbon sources in VWPs by optimizing the synchronous saccharification fermentation conditions.The solid-liquid ratio was 1:20,and 6.3 g/L of oil was obtained on the third day of fermentation.and there was no significant difference in fatty acid composition between the two fermentation methods.