Lipases are enzymes that catalyze the hydrolysis of carboxylic esters at a lipid–water interface and are able to catalyze reactions such as alcoholysis, esterification, transesterification, and enantioselective synthesis in organic media. They are important biocatalysts for biotechnological and industrial applications—such as in the food and flavor industry—and in the production of biopharmaceuticals, biofuels, biopolymers, and detergents. A desirable property of lipases is stereoselectivity for the production of chemicals with high optical purity. In this work, we report the improvement of the enantioselective capabilities of the Geobacillus thermoleovorans CCR11 lipase. By means of a rational design and bioinformatic approaches, six amino acids of the catalytic cavity of the lipase LipTioCCR11 were substituted resulting in an increase in the optimum temperature of the enzyme and in the resistance to the presence of organic solvents in hydrolytic reactions, and in the promotion of the enantioselective recognition of R isomers of carboxylic acids with importance for the pharmaceutical and food industries.
Los Humeros volcanic complex, located at the eastern end of the Trans Mexican Volcanic Belt, possess superficial thermal manifestations (fumaroles, heat steam-soils and alteration zones), with temperatures between 50 °C and 90 °C. This is the first work to explore the bacterial diversity of a steam soil of Los Humeros geothermal field using a metagenomic 16S RNA gene analysis, and the presence of lipolytic enzymes’ genes after an enrichment culture by a whole-genome shotgun approach. High diversity indexes were found in soil samples, with Firmicutes, Chloroflexi, Proteobacteria, Actinobacteria and Acidobacteria as the most prevalent phyla. Alicyclobacillus was the most prevalent genus at 15 cm and Anoxybacillus at 50 cm depth; anaerobic and obligate thermophilic and hyperthermophilic members were found at 50 cm depth. Firmicutes was favored by the oil-rich medium, and the dominant genera were Geobacillus and Caldibacillus. 165 genes related to lipolytic enzymes were found; carboxilesterases and phospholipases C were the most abundant, and 43% were assigned to uncharacterized lipolytic enzymes. The diversity as well as the high percentage of non-characterized lipolytic enzymes found after soil enrichment in an oil-rich medium suggest the presence of biotechnologically promising organisms and enzymes that deserve to be investigated.
Lipases and carboxylesterases are enzymes of biotechnological interest both for their reactions and their specificity. They have wide-ranging applications in the food, pharmaceuticals, biodiesel synthesis, and bioremediation industries. For that reason, the strain Neobacillus thermocopriae C255 was isolated from ash from Popocatepetl volcano and studied as a new source of lipolytic enzymes. It was identified using 16S ribosomal RNA and flagellar protein FliF sequence homology, yielding 100% identity. From the sequencing of its genome, an enzyme with lipolytic activity, classified as a monoacylglycerol lipase, and named Mgl-C255, was cloned in E. coli BL21, and then expressed, biochemically characterized, and tested via transesterification reactions with alcohols and monosaccharides. Based on its sequence and structure, it was placed within family V, having a catalytic triad of S90-D207-H237. Biochemical characterization showed its highest activity at 40 °C, pH 7.5 to 8.5, with C-2 length substrate preference. No metal ions or inhibitors influenced lipolytic activity, except for PMSF, SDS, Cu−2, and Hg−2. Mgl-C255 retained about 50% of its activity in non-polar solvents and showed synthetic activity in organic solvents, making it a good candidate for studying its catalytic potential and selectivity.
Hydrolases are the most popular enzymes, and among the most valuable in biotechnological applications. Some hydrolases, such as lipases, esterases, proteases, cellulases and amylases, are used in the food industry and the production of biopharmaceuticals, biofuels, biopolymers and detergents. Of special interest are those obtained from thermophilic microorganisms. Although there is great microbial diversity in extreme environments, the investigations aimed at detecting and isolating enzymes with potential for polyester degradation such as polyethylene terephthalate (PET) are limited. In this work, we explored the metagenomic library of an oil-enriched soil sample from the “Los Humeros” geothermal field by means of in silico probes in search for enzymes potentially able to degrade polyesters. Using conserved motifs and activity-relevant sites of reported polyester hydrolases, we designed probes that allowed us to identify 6 potential polyester hydrolases in the metagenome. Three-dimensional structure prediction revealed a canonical α/β fold and a cap covering the active site of the enzymes. The catalytic triads were composed of Ser, His and Asp. Structural comparison, substrate binding site analysis and molecular docking suggested their potential as polyester hydrolases, particularly cutinases and PETases. An enzyme, REC98271, was cloned, expressed and characterized, showing thermophilic properties and preference for short-chain substrates. These findings contribute to our understanding of enzyme diversity in “Los Humeros” metagenome and their potential applications in biodegradation and recycling processes.