The Preparation Of Microbial Oil-based Lubricant And The Elementary Study Of The Homologue's Tribological Properties

In this paper, the preparation of a new type of microbial oil and its related tribological properties were studied. The microbial oil was obtained by fermentation, and transesterification method was used for chemical modification of microbial oil. Schiff base copper complex were and, then, a new type of green oil was prepared.In the process of preparation of microbial oil, Yarrowia lipolytica,Rhodosporidium toruloides,Cunninghamella blakelean,Mortierella isabellina were used to pruduct Microbial oil. By comparison, with the highest oil content of dry fungus of Mortierella isabellina was selected as the original strain to mass the production of microbial oil.A rapid detection method of fungal oil content was established after microwave pretreating, and gas chromatography (GC) was employed to analysis. The wet cell pretreated by microwave, reacted directly with KOH-CH3OH,and the reaction product, which is glycerol triacetate,was detected by gas chromatography analysis to ascertain the fat content in microorganisms. The results show that the established method of rapid determination of fat content fungal had good precision, accuracy and reliability, the method recoveries was 97.99%-104.96%. The microwave pretreating could improve the oil extraction rate significantly by GC,and SEM analysis also proved the significant effect of microwave pretreatment. The microwave pretreatment time of 2 min at 420W, the saponification reaction time of 2min at 140W, the glycerol esterification time of 10 min were the best.To reduce the costs and improve raw material utilization, the microbial fermentation process optimization was studied. The results showed that microbial oil with rapeseed meal fermentation medium is feasible and the feasibility of two-step fermentation of oil was better than one-step fermentation. Meanwhile, with the fermentation time of 5 d and medium carbon and nitrogen ratio of 86:1, mycelium could obtain the highest oil content of dry bacteria.To improve the extraction efficiency of microbial oils, the methanol extraction of cell oil was studied after microwave treatment. And a new microbial oil extraction was carried on. The results showed that the best conditions of methyl extraction were: liquid ratio of 1:5, temperature of 50℃, KOH-methanol concentration of 2.5%, the time of 2h.The microbial oil was modified by transesterificating, and the Schiff base copper complex was prepared in modified microbial oil directly by microemulsion system. The homologue's tribological properties were studied, results showed that the microbial oil as a lubricant base oil is feasible.