Date Published: June 5, 2018
Publisher: Springer Berlin Heidelberg
Author(s): Yuzhou Wang, Rui Ma, Shigui Li, Mingbo Gong, Bin Yao, Yingguo Bai, Jingang Gu.
Alkaline lipases with adaptability to low temperatures and strong surfactant tolerance are favorable for application in the detergent industry. In the present study, a lipase-encoding gene, TllipA, was cloned from Trichoderma lentiforme ACCC30425 and expressed in Pichia pastoris GS115. The purified recombinant TlLipA was found to have optimal activities at 50 °C and pH 9.5 and retain stable over the pH range of 6.0–10.0 and 40 °C and below. When using esters of different lengths as substrates, TlLipA showed preference for the medium length p-nitrophenyl octanoate. In comparison to commercial lipases, TlLipA demonstrated higher tolerance to various surfactants (SDS, Tween 20, and Triton X100) and retained more activities after incubation with Triton X100 for up to 24 h. These favorable characteristics make TlLipA prospective as an additive in the detergent industry.
Lipase (EC 126.96.36.199) is regarded as one of the most important commercial enzymes, and has been attracting enormous attention in the rapidly growing biotechnological area. It catalyzes the hydrolysis of triacylglycerols to release diacylglyceride, monoacylglycerol, long-chain fatty acids (> 8 carbons) and glycerol at the interface of oil and water (Brockerhoff 1974). According to the protein structure similarity, lipase belongs to the family of α/β hydrolases, in which a catalytic triad (usually serine, histidine, and aspartic or glutamic acid) and an oxyanion hole (just like a catalytic pocket) are crucial for catalysis (Gupta et al. 2015), and a lid structure involves in the substrate accessibility and binding in the active site (Woolley and Petersen 1996). During hydrolysis, the hydroxy group of the catalytic serine attacks the carbonyl carbon of the ester bond of the substrate, while the catalytic histidine acts as a general-base catalyst and abstracts a proton from the catalytic serine. The alcohol group of the substrate is released and an acyl-enzyme intermediate is formed, which is stabilized in the oxyanion hole by hydrogen bonds. The acyl-enzyme intermediate can be attacked by a water or alcohol molecule, leading to the formation of acid or new ester, respectively (Beer et al. 1996).
The genus Trichoderma contains a very large group of important microorganisms. It is not only a genetic resource of various functional proteins (Freitas et al. 2014) but also a key workhorse for enzyme production on commercial scale (i.e. T. reesei) (Jørgensen et al. 2014). In the present study, we reported an alkaline, mesophilic lipase-producing strain (ACCC30425) of T. lentiforme. Along with the rapid progress of genome sequencing (Yang et al. 2015), to obtain objective genes with special characters is very simple and efficient. Based on the sequence analysis and annotation of the genome of T. lentiforme ACCC30425, the full-length TllipA was identified and its structure and functions were predicted. Although TllipA shows high sequence identity (100%) to the hypotheoretical lipase from T. guizhouense, its identities to lipases with function verified or structure resolved are much lower (< 50%). Thus it is of importance and novelty to clone the gene and produce the gene product for potential applications in various industries. Source: http://doi.org/10.1186/s13568-018-0618-z