Study on preparing fatty acid by hydrolyzing Jatropha Curcasl Oil with lipase
Used tween-80 as emulsifier, industrial lipase as catalyst to hydrolyze Jatropha Curcasl Oil and make mixed fatty acid. We discussed the enzyme concentration, substrate concentration, temperature and time on hydrolysis. Through the experiment, we found that when we used emulsifier which contains 2% oil in the system, we could get the optimal parameter for hydrolysis of waste oil from restaurants as follows: concentration of catalyst 4% (W/W), weight ratio of oil to water 1:4 (W/W), temperature at 40°C, and hydrolysis time is 32h. Under these conditions, the AV(acid value) of hydrolyzed rapeseed oil reached 163.2 mg KOH/g, and hydrolytic rate arrived at 89.6%.
Lipase catalyzed alcoholysis of sunflower oil
Lipase-catalyzed alcoholysis of sunflower oil under anhydrous conditions was examined. Lipases fromPseudomonas fluorescens and 2 immobilized enzymes fromMucor miehei and aCandida sp. gave sufficient conversion with petroleum ether as the solvent, even when methanol and ethanol were used. The overall content of tri-, di- and monoglycerides, as well as the corresponding alkyl esters, was measured. BecausePseudomonas lipase led to almost quantitative esterification, further studies were carried out with that enzyme varying the amounts of enzyme or the alcohols. Acceptable conversions were achieved even without solvent. Reaction rates of alcoholysis with 5 homologous alcohols, with or without the addition of water, were measured, and in all cases the reaction rates increased with higher chain length of the alcohol. In the case of methanol the highest rate was obtained without any addition of water, but a significantly higher rate was observed with 96% ethanol as opposed to absolute ethanol. The main advantages of lipasecatalyzed, nonaqueous alcoholysis as compared to classical procedures are the mild reaction conditions, the isolation of glycerin without further purification and without the formation of chemical waste, and the ability of lipases to catalyze the esterification of free fatty acids.
Gut immunity in Lepidopteran insects.
Lepidopteran insects constitute one of the largest fractions of animals on earth, but are considered pests in their relationship with man. Key to the success of this order of insects is its ability to digest food and absorb nutrition, which takes place in the midgut. Because environmental microorganisms can easily enter Lepidopteran guts during feeding, the innate immune response guards against pathogenic bacteria, virus and microsporidia that can be devoured with food. Gut immune responses are complicated by both resident gut microbiota and the surrounding peritrophic membrane and are distinct from immune responses in the body cavity, which depend on the function of the fat body and hemocytes. Due to their relevance to agricultural production, studies of Lepidopteran insect midgut and immunity are receiving more attention, and here we summarize gut structures and functions, and discuss how these confer immunity against different microorganisms. It is expected that increased knowledge of Lepidopteran gut immunity may be utilized for pest biological control in the future.