Investigation of Lipolytic-Secreting Bacteria from an Artificially Polluted Soil Using a Modified Culture Method and Optimization of Their Lipase Production

Compared to lipases from plants or animals, microbial lipases play a vital role in different industrial applications and biotechnological perspectives due to their high stability and cost-effectiveness. Therefore, numerous lipase producers have been investigated in a variety of environments in the presence of lipidic carbon and organic nitrogen sources. As a step in the development of cultivating the unculturable functional bacteria in this study, the forest soil collected from the surrounding plant roots was used to create an artificially contaminated environment for lipase-producing bacterial isolation. The ten strongest active bacterial strains were tested in an enzyme assay supplemented with metal ions such as Ca2+, Zn2+, Cu2+, Fe2+, Mg2+, K+, Co2+, Mn2+, and Sn2+ to determine bacterial tolerance and the effect of these metal ions on enzyme activity. Lipolytic bacteria in this study tended to grow and achieved a high lipase activity at temperatures of 35–40 °C and at pH 6–7, reaching a peak of 480 U/mL and 420 U/mL produced by Lysinibacillus PL33 and Lysinibacillus PL35, respectively. These potential lipase-producing bacteria are excellent candidates for large-scale applications in the future.

A Valuable Product of Microbial Cell Factories: Microbial Lipase

As a powerful factory, microbial cells produce a variety of enzymes, such as lipase. Lipase has a wide range of actions and participates in multiple reactions, and they can catalyze the hydrolysis of triacylglycerol into its component free fatty acids and glycerol backbone. Lipase exists widely in nature, most prominently in plants, animals and microorganisms, among which microorganisms are the most important source of lipase. Microbial lipases have been adapted for numerous industrial applications due to their substrate specificity, heterogeneous patterns of expression and versatility (i.e., capacity to catalyze reactions at the extremes of pH and temperature as well as in the presence of metal ions and organic solvents). Now they have been introduced into applications involving the production and processing of food, pharmaceutics, paper making, detergents, biodiesel fuels, and so on. In this mini-review, we will focus on the most up-to-date research on microbial lipases and their commercial and industrial applications. We will also discuss and predict future applications of these important technologies.

Lipolytic Activities of Bacteria and Fungi Isolated from Soil Samples

This study was carried out at the Department of Microbiology, Microbiology Laboratory, Ado-Ekiti State University, Ekiti State, Nigeria between July, 2018 to March, 2019. Due to the diverse biotechnological importance of lipases as a biocatalytic enzyme, extracellular production of microbial lipases has to gain lots of interest. This study, therefore, focused on the physicochemical parameters of lipase producing microorganisms from different soil samples. Microorganisms were isolated from four different soil samples using Nutrient Agar (NA) and Potato Dextrose Agar (PDA). The isolates were identified and characterized. Production, an assay for Lipase enzymes, purification, the effect of pH, Temperature and metal ion was investigated. The isolates were culturally, morphologically and biochemically characterized. Two of the bacteria strains (Bacillus sp. and Staphylococcus sp.) and four fungi (Fusarium sp., Aspergillus fumigatus, Aspergillus niger, and Trichophyton sp.) isolates were able to produce lipid using Sudan Black B Fat staining techniques. Fusarium sp. isolated from dumpsite soil had the highest specific lipase activity (21.16 µmol/min/ml) while Bacillus sp. isolated from red oil spill soil had the highest lipase activity (0.59 µmol/min/mg). The specific activity of partially purified lipase for Fusarium sp. was 2.39 µmol/min/mg while Bacillus sp. had a specific activity of 2.46 µmol/min/mg. 30oC - 50oC, pH 7.0 to 9.0 and KCl2 (139.672%) supported the highest production of lipase by the Bacillus sp. and Fusarium sp. This study demonstrated that the Bacillus sp. produced a high amount of lipase activity followed by Fusarium sp. Extensive and persistent screening for new microorganisms and their lipolytic activities will help to provide faster ways to solve most environmental soil pollution.

Various Perspectives on Microbial Lipase Production Using Agri-Food Waste and Renewable Products

Lipases are enzymes that catalyze various types of reactions and have versatile applications. Additionally, lipases are the most widely used class of enzymes in biotechnology and organic chemistry. Lipases can be produced by a wide range of organisms including animals, plants and microorganisms. Microbial lipases are more stable, they have substrate specificity and a lower production cost as compared to other sources of these enzymes. Although commercially available lipases are widely used as biocatalysts, there are still many challenges concerning the production of microbial lipases with the use of renewable sources as the main component of microbial growth medium such as straw, bran, oil cakes and industrial effluents. Submerged fermentation (SmF) and solid-state fermentation (SSF) are the two important technologies for the production of lipases by microorganisms. Therefore, this review focuses on microbial lipases, especially their function, specificity, types and technology production, including the use of renewable agro-industrial residues and waste materials.