| Decades of underinvestment in the energy sector coupled with an ongoing lack of financing for fossil fuel energy that continues to drive a large share of our economy’s energy input have stalled economic growth and contributed to a global energy crisis.The world lacks safe,low-carbon,and cheap large-scale energy alternatives to fossil fuels until we scale up those alternatives.An algal fatty acid photodecarboxylase from Chlorella variabilis NC64A(CvFAP)was found.This flavoenzyme catalyzes the light-dependent decarboxylation of some long-chain fatty acids to the corresponding C1-shortened alkanes and proposed as an alternative approach for the synthesis of biodiesel.Hydrocarbon alkanes,components of major fossil fuels,are considered as next-generation biofuels and ideal alternative for fossil fuels.Light-driven photoenzyme-catalyzed decarboxylation of fatty acid convert into alkenes,is more energy-saving and environmentally friendly with the advantages of high efficiency,no by-products,mild conditions,have broaden its development.Yet bioenzyme is very sensitive and unstable.Hence,the large-scale or industrialized use of enzyme is restricted.In order to improve the catalytic efficiency,recovery and reduce the cost has become the research hotspot of enzymatic catalysis,different catalytic reaction systems have investigated.In this work,a new type of multi-phase emulsion photoenzymatic catalytic system was constructed on the basis of a novel catalytic system —— the three liquid phase system.The catalytic effects and application of fatty acid photodecarboxylase(CvFAP)were tested and verified.The feasibility of enriching polyunsaturated fatty acids in fish oil by photocatalytic method was explored.(1)The culture medium of recombined engineered Escherichia coli(E.coli BL21(DE3)-p ET28a-CvFAP)was optimized by Response Surface Analysis and single factor optimization.Then,the culture conditions in the shake flask fermentation were optimized by the single factor method,and the optimal fermentation conditions were determined.the enzyme activity of CvFAP can reach 2245.81 U/L in the optimized condition,The yield of CvFAP product in the optimized medium was increased by 54%.(2)Basic on our previous work,a novel multi-phase cell-like emulsion photoenzymatic catalytic system was constructed by using combination of salts and wholecell catalysis.The results showed that the addition amount of lipase MAS1 was 30 mg/m L,CvFAP was 0.2 g/m L,p H 8.5,at 37 °C.12 h,the yield of alkene was higher than 95%.Meanwhile,decarboxylation of different types of oils and fats were investigated.Except for castor oil,the conversions were greater than 95%.(3)The fatty acid photodearboxylase(CvFAP)was coupled with lipase to enrich polyunsaturated fatty acid(PUFA)in fish oil by three liquid phases system.After optimized the conditions 65% of PUFA was enriched and 85.38% of recovery.The use of the enzymes was investigated.The results showed that after 8 batch repeated use,there was no significant decrease in lipase activity,49% of PUFA and 70% of recovery was abstained. |
