Study Of Fermentation Conditions Optimization And Immobilization On Lipase From Bacillus Licheniformis

Lipases(EC 3.1.1.3) are a class of enzymes which catalyse the hydrolysis of long chain triglycerides. Lipases constitute the most important member of biocatalysts in industrial applications. In recent years, with the rapid development of enzyme technology, the mechanism of action and application range of lipase have been constantly found and extended, microbial lipases are currently receiving much attention.Microbial lipases have been widely applied to various industrial fields, including:detergent, spices, energy, food industry, chemical synthesis, cosmetics, biological sensors, biological degradation, esters and amino acid derivatives, and so on.Enzymes are considered as nature’s catalysts, while most enzymes used for industrial applications today are produced by the fermentation of microbial materials. With the increasing demand for industrial application of lipase, in addition to looking for new type of lipase production strains and genetic modification of the existing strains, it’s imperative to use scientific and reasonable experimental design method to optimize the fermentation conditions of enzyme production to improve the lipase production or use of immobilized enzymes to improve the utilization rate of lipase. This research topic is put forward in this background.Our laboratory has built a recombinant strain of bacillus subtilis WB700, which can express an extracellular lipase Bli02525 from bacillus licheniformis. Our research makes this recombinant strain as the research object, through using the response surface methodology (RSM) to optimize its enzyme production conditions and using an amino type carrier ZH-HA to immobilize the extracellular lipase. At last, we study the differences before and after the immobilization of the extracellular lipase. After the optimization by RSM, we get the optimal culture medium and use it for 10 L fermentation. When the fermentation to 30 h, the total enzyme activity of supernatant is up to 46 U/mL, which is 2.6-fold increased than shake flask culture before optimization 17.3 U/mL. After immobilization by ZH-HA, the optimal reaction pH at about 10.0 and the optimal reaction temperature is 45 ℃. This immobilized enzyme is very stable, The residual enzyme activity can retain more than 90% after repeated use 15 batches, which greatly increased the repeat utilization of enzymes. This results will provide theoretical support for the industrial production of lipase.