Simultaneous immobilization-purification of a microbial lipase for biodiesel production

Background and Aim : Serious reduction of fossil fuels resources together with the world increase of greenhouse gas emissions and ecological pollution have led to the quest for alternative renewable and clean fuels. Up to now, almost ۱۰۰% of transportation energy and ۸۶% of the global energy consumption are provided by fossil fuels. Fatty acid alkyl esters (FAAEs) are introduced as a promising alternative of diesel that named biodiesel. The aim of this study, is to introduce a heterogeneous biocatalyst of SBA-۱۵@oleate@lipase for biodiesel production.Methods : In the present study, a mesoporous silica of SBA-۱۵ modified with oleic acid and a solvent tolerant lipase from Actinomadura sediminis (SBA-۱۵@oleate@lipase) was designed as the heterogeneous biocatalyst with maximum activity by a protein loading of ۳۲.۰ mg per gram of the support. The enzymatic trans-esterification reaction was catalyzed for converting oil of the cyanobacterium Synechococcus elongatus into biodiesel. The physico-chemical characteristics of the cyanobacterial oil and biodiesel were estimated using biodiesel analyzer software and compared with the standards of ASTM D۶۷۵۱.Results : The maximum immobilization efficiency (۶۸%) and yield (۸۰%) were also obtained at ۲۰۰ μg ml−۱ of the protein with reaction time of ۶۰ min. The enzymatic trans-esterification reaction was performed with an ۸۵%±۳.۲ yield under optimized conditions. The designed heterogeneous biocatalyst revealed a high efficiency towards palmitoleic acid (C۱۶:۱) in the microalgal oil that is one of the best fatty acids to produce a high-quality biodiesel. The produced biodiesel demonstrated suitable cetane number and oxidative stability compared with the standards of ASTM D۶۷۵۱.Conclusion : This work also highlights the simultaneous combination of purification and immobilization of the bacterial lipase by interfacial activation mechanism, to the synthesis of a solid biocatalyst for production of a cyanobacterium-based biodiesel.

کلیدواژه ها:

Biodiesel ، Immobilization ، SBA-۱۵@oleate@lipase