Lipase from new isolate Bacillus cereus ATA179: optimization of production conditions, partial purification, characterization and its potential in the detergent industry

UV mutagenesis for lipase overproduction from Bacillus cereus ATA179, nutritional optimization, characterization and its usability in the detergent industry

In this study, the wild-type Bacillus cereus ATA179 was mutagenized by random UV mutagenesis to increase lipase production. The mutant with maximum lipolytic activity was named Bacillus cereus EV4. The mutant strain (10.6 U/mL at 24 h) produced 60% more enzyme than the wild strain (6.6 U/mL at 48 h). Nutritional factors on lipase production were investigated. Sucrose was the best carbon source, (NH4)2HPO4 was the best nitrogen source and CuSO4 was the best metal ion source. Mutant EV4 showed a 32% increase in lipase production in the modified medium. The optimum temperature and pH were found to be 60 °C and 7.0, respectively. CuSO4, CaCl2, LiSO4, KCl, BaCl2, and Tween 20 had an activating effect on the enzyme. Vmax and Km values were found to be 17.36 U/mL and 0.036 mM, respectively. The molecular weight was determined as 28.2 kDa. The activity of lipase was found to be stable up to 60 days at 20 °C, 75 days at 4 °C, and 90 days at -20 °C. The potential of lipase in the detergent industry was investigated. The enzyme was not affected by detergent additives but was effective in removing stains in fabrics contaminated with oily substances.

Production of Extracellular Lipase by Bacillus halotolerans from Oil-Contaminated Soil in a Pilot-Scale Submerged Bioreactor

Microbial lipases are the biocatalyst of choice for the present and future because of their characteristics, including their ability to remain active as an enzyme throughout a broad pH, temperature, and substrate range. The goal of the current investigation was to find novel sources of substrates and isolates from soil contaminated by oil for the synthesis of lipase. On tributyrin media, 10 lipolytic bacterial strains that were isolated from oil-contaminated soil were grown. Using the zone of clearance, it was possible to identify the isolates with the highest activity. Following phylogenetic tree analysis, molecular characterization of the 16S rRNA sequence of the bacterial isolates revealed that it was Bacillus halotolerans (VSH 09). The enzyme was purified to near homogeneity. The enzyme activity was found to be optimum at a pH of 7.0 and a temperature of 35 °C. While Ni2+ and Cu2+ had no effect, the presence of Mg2+ and Ca2+ exhibited the highest levels of enzyme activity. At 1%, tributyrin as a substrate exhibited its highest level of activity. The molecular weight, as determined by SDS-PAGE, was found to be 38 kDa. The kinetics of the enzyme were found to be 41.66 and 9.37 mg/mL for Vmax and Km, respectively. The high yield of lipase produced by this method suggests that it holds potential for production on a large scale and could be used for various biotechnological applications.

Bacillus cereus (EG-Q3) in the Gut of Ectropis grisescens Contributes to Host Response to Starvation Conditions

The gut bacteria of insects play an important role in their nutrition, maintenance, and ecological adaption. Ectropis grisescens is the most important leaf-feeding pest in tea gardens in China. In order to explore whether E. grisescens adaptation under starvation stress is related to its gut bacteria, we used a culture-independent method to compare the composition and diversity of their gut bacteria under starvation treatment. The results revealed no significant changes in core gut bacteria composition and diversity within 24 h of starvation. However, non-core gut bacterial Bacillus increased significantly under starvation conditions. B. cereus strain EG-Q3 isolated from the gut of E. grisescens in carbon source-selected medium showed the ability to degrade fat bodies from E. grisescens in vitro and in vivo. Moreover, the fat-lowering ratio of E. grisescens fed with B. cereus strain EG-Q3 (6.76 ± 1.281%) was significantly higher than that of the control group (3.96 ± 0.801%, t = 4.15, df = 8, p < 0.01) after starvation for 4 h. These findings suggest that non-core gut bacterial B. cereus strain EG-Q3 contributes to host adaptation to starvation. Together, this research provides evidence that E. grisescens may benefit from non-core gut bacteria under starvation conditions.