Effect of cross-linked enzyme aggregate strategy on characterization of sn-1,3 extracellular lipase from Aspergillus niger GZUF36.

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Effect of cross-linked enzyme aggregate strategy on characterization of sn-1,3 extracellular lipase from Aspergillus niger GZUF36.

Appl Microbiol Biotechnol. 2021 Feb 09;:

Authors: Zhu R, Li C, Chen C, Xing S, Cai Y, Zeng X, He L

Abstract
The sn-1,3 extracellular lipase from Aspergillus niger GZUF36 (EXANL1) has important potential applications. The cross-linked enzyme aggregate (CLEA) of purified EXANL1 (CLEA-EXANL1) achieved optimum activity recovery (148.5 ± 0.9%), immobilization yield (100 ± 0%), and recovered activity (99.7 ± 0.6%) with 80% tert-butanol as the precipitant, glutaraldehyde (GA) concentration of 30 mM, GA treatment time of 1.5 h, and centrifugal speed of 6000×g. The effect of CLEA strategy on the characterization of EXANL1 was evaluated in this work. CLEA-EXANL1 exhibited a broader optimum pH range (4-6) compared with free EXANL1 (6.5). CLEA-EXANL1 presented optimum activity at 40 °C, which was 5 °C higher than that of free EXANL1. CLEA strategy decreased the maximum reaction rate and increased the Michaelis-Menten constant of EXANL1 when olive oil emulsion was used as a substrate. Moreover, after 30 days, free EXANL1 lost more than 80.0% of its activity, whereas CLEA-EXANL1 retained more than 90.0% of its activity. CLEA strategy improved the tolerance of EXANL1 in polar organic solvents. Fourier transform infrared spectroscopy results showed that the CLEA technique increased the contents of β-sheets and β-turns in EXANL1 and reduced those of α-helixes and irregular crimps. CLEA strategy caused no change in the sn-1,3 selectivity of EXANL1. Therefore, EXANL1 in the form of CLEA is a valuable catalyst in the synthesis of 1,3-diacylglycerol. KEY POINTS: • Cross-linked enzyme aggregate (CLEA) strategy broadened the optimum pH range of sn-1,3 extracellular lipase from Aspergillus niger GZUF36 (EXANL1). • CLEA strategy improved the tolerance of EXANL1 in polar organic solvents. • CLEA strategy caused no change in the positional selectivity of EXANL1.

PMID: 33559718 [PubMed – as supplied by publisher]

Source: Industry