Evaluation of steam-exploded green coconut fiber as support for the immobilization of lipases fromPseudomonas fluorescens,Candida antarcticaB, and Eversa.

The application of steam-exploded green coconut fiber (GCF) (an agro-industrial waste) was studied as a support for the immobilization of lipases, using lipase B from Candida antarctica (CALB), lipase from Pseudomonas fluorescens (PFL) or the engineered lipase Eversa (EL) as model enzymes. The achieved immobilization yield was 82.01 ± 2.02%, 87.62 ± 4.34%, and 77.47 ± 1.88% for GCF-PFL and GCF-CALB in 24 h, and GCF-EL in 48 h, respectively. The biocatalysts' activities (U/mg) and recovered activities in relation to the soluble enzymes (%) were 10.22 ± 0.96 U/mg and 26.37 ± 2.25%, 9.22 ± 0.17 U/mg and 49.84 ± 2.30%, 27.23 ± 0.21 U/mg and 9.48 ± 0.11% for GCF-CALB, GCF-PFL, and GCF-EL, respectively. After the immobilization, the enzymes were subjected to modification with glutaraldehyde (GA) or/and polyethylenimine (PEI). The modification with both GA and PEI was the best achievement as it reduced the desorption of lipases from the support and substantially increased their thermostability (for GCF-CALB-GA-PEI: stabilization factor (SF) > 154.8 at 60 ºC; for GCF-PFL-GA-PEI: SF > 58.6 at 75 ºC and GCF-EL-GA-PEI: SF > 172.6 at 80 ºC). The maximum enzyme load was determined to be 5 mg/g for CALB biocatalysts, 10 mg/g for PFL and EL. This study shows an alternative use of this agroindustrial, with the environmental relevance that it presents.