Activity of a recombinant lipase (LipC12) in selected reactions with applications in oleochemistry

SANCHEZ D.; ALNOCH R.; TONETTO G.; KRIEGER N.; FERREIRA M.

Florianopolis

Congreso; XIII ENZITEC - Seminário Brasileiro de Tecnologia Enzimática; 2018

Universidade Federal de Santa Catarina y Universidade Federal da Fronteira Sul

The free recombinant lipase LipC12 was tested in the synthesis of pentyloleate (molar ratio alcohol:acid=2:1, 40 ̊C, 5 h) and in the hidrolysis of soybean oil (molar ratio water:oil=10:1, 40 ̊C, 5 h), both in n-heptane. The relative amount of crude LipC12 was up to 15% in relation to oleic acid or soybean oil mass. Without water (0%), LipC12 was inactive in esterification. Adding water from 2.5 to 17.5% ( w/w, related to oleic acid), the conversion of oleic acid into to ester in n-heptane increased up to 75 %, with the maximum at 2-3% of water, whereas, from 0 to 20% of water (related to oleic acid mass) the conversion achieved 45%. The hydrolysis of triglycerides in soybean oil reached 33%, whereas selectivity to diglycerides and monoglycerides was 58% and 7%, respectively. The conversion of triglycerides reached 13% after 1h. In this case, the selectivity to diglycerides and monoglycerides was 74% and 14%, respectively.Free crude recombinant LipC12 needs a substantial amount of water to be active in the hydrolysis of soybean oil. For esterification reactions, as the water content increases, lower equilibrium conversions are achieved. Initial substrate mixtures in n-heptane with no water added are stable as a single liquid phase. In biphasic systems with water present from the begining, the aqueous phase is where the water generated by reaction is partitioned. Around the lipase, an interphase organic medium/water is available. Several authors have found optimal enzymatic activity in systems with initial water contents approximately 0?3%. For esterifications the activating effect of water dominates at water contents below the optimum while at higher water contents the net esterification rates decrease, which may be a result of water acting as a substrate in hydrolysis of the acyl-enzyme intermediate.