Applied Biocatalysis with an Organic Resistant Partially Purified Lipase from P. aeruginosa During FAME Production

Abstract

A partially purified lipase from the Pseudomonas aeruginosa strain (PSA-01) isolated from the palm oil fruit Elaeis guineensis was used as biocatalyst to produce fatty acid methyl esters (FAME). Lyophilized lipase supernatant (LLS) was used during the first step to screen the main variables (pH, temperature, stoichiometric oil:methanol ratio, water content and type of oil). Other variables which were identified during the screening assays (scale of reaction recipient, LLS amount and use of hexane to solubilize methanol forming a methanol-oil microemulsion) were tested during a second step. The response variable was % molar yield of FAME. It was quantified by GC. Additionally, the LLS work parameters were optimized and compared to a partially purified lipase (PPL) during a final assay. The first-order interactions between the analyzed factors were significant (p<0.05). The highest yield was 4.16% w/w (respect to oil) using a partially purified lipase (PPL) with pH 8, refined, bleached, and deodorized oil (RBD), 5% water (by volume) in oil and 10% hexane (by volume), and a stoichiometric ratio of 1:170 oil:methanol. The final assay was carried out at 54°C and 200 rpm for 48 hours. It resulted in a 34.68% conversion using PPL. It also showed a 13-fold improvement versus the initial yield with LLS, suggesting the need for a better purification process. During this research, the lipase was partially purified and used at an alkaline pH. It showed resistance to organic compounds such as methanol and hexane. This implies great potential to act as an effective biocatalyst in the implementation of biodiesel production processes.