Many microorganisms, especially bacteria, produce biosurfactants when grown on water-immiscible substrates. Biosurfactants are more effective, selective, environmentally friendly, and stable than many synthetic surfactants. Most common biosurfactants are glycolipids in which carbohydrates are attached to a long-chain aliphatic acid, while others, like lipopeptides, lipoproteins, and heteropolysaccharides, are more complex. Rapid and reliable methods for screening and selection of biosurfactant-producing microorganisms and evaluation of their activity have been developed. Genes involved in rhamnolipid synthesis (rhlAB) and regulation (rhlI and rhlR) in Pseudomonas aeruginosa are characterized, and expression of rhlAB in heterologous hosts is discussed. Genes for surfactin production (sfp, srfA, and comA) in Bacillus spp. are also characterized. Fermentative production of biosurfactants depends primarily on the microbial strain, source of carbon and nitrogen, pH, temperature, and concentration of oxygen and metal ions. Addition of water-immiscible substrates to media and nitrogen and iron limitations in the media result in an overproduction of some biosurfactants. Other important advances are the use of water-soluble substrates and agroindustrial wastes for production, development of continuous recovery processes, and production through biotransformation. Commercialization of biosurfactants in the cosmetic, food, health care, pulp- and paper-processing, coal, ceramic, and metal industries has been proposed. However, the most promising applications are cleaning of oil-contaminated tankers, oil spill management, transportation of heavy crude oil, enhanced oil recovery, recovery of crude oil from sludge, and bioremediation of sites contaminated with hydrocarbons, heavy metals, and other pollutants. Perspectives for future research and applications are also discussed.

Microbial production of surfactants and their commercial potential.

Lipases, triacylglycerol hydrolases, are an important group of biotechnologically relevant enzymes and they find immense applications in food, dairy, detergent and pharmaceutical industries. Lipases are by and large produced from microbes and specifically bacterial lipases play a vital role in commercial ventures. Some important lipase-producing bacterial genera include Bacillus, Pseudomonas and Burkholderia. Lipases are generally produced on lipidic carbon, such as oils, fatty acids, glycerol or tweens in the presence of an organic nitrogen source. Bacterial lipases are mostly extracellular and are produced by submerged fermentation. The enzyme is most commonly purified by hydrophobic interaction chromatography, in addition to some modern approaches such as reverse micellar and aqueous two-phase systems. Most lipases can act in a wide range of pH and temperature, though alkaline bacterial lipases are more common. Lipases are serine hydrolases and have high stability in organic solvents. Besides these, some lipases exhibit chemo-, regio- and enantioselectivity. The latest trend in lipase research is the development of novel and improved lipases through molecular approaches such as directed evolution and exploring natural communities by the metagenomic approach.

Bacterial lipases: an overview of production, purification and biochemical properties.

Lipase promiscuity and its biochemical applications

Regiospecificity is one of the major advantages of using lipase technology for the modification of oils and fats to produce high-value added products, such as cocoa butter equivalents, human milk fat substitutes, and other specific-structured lipids. Due to the high cost of biocatalysts, the mainstream applications of lipases for normal oils and fats are still limited. Therefore, positional specificity of lipases has the priority and will be the target property to be exploited for commercial and industrial developments, because no chemical method has such a specificity and is promising or possible for this task. In this paper, encouraging products resulting from this regiospecificity are reviewed together with the critical evaluation of their reaction schemes, side reactions and by-products, sources of substrate oils and acyl donors, and production processes.

Production of specific‐structured triacylglycerols by lipase‐catalyzed reactions: a review

Lipases are endowed with a substrate specificity that surpasses that of any other known enzyme. This confers on these enzymes an application potential that is literally boundless. Lipases can be employed in the production of pharmaceuticals, cosmetics, leather, detergents, foods, perfumery, medical diagnostics, and other organic synthetic materials. This review attempts to present a comprehensive discussion on the present status of this unique group of enzymes in industry, as well as the actual potential. It represents an endeavor to provide a sincere answer to the question, “What can be done with this enzyme?” as well as, “Can lipase be utilized for this purpose?” It is intended that the manuscript will cover or at least mention all known applications, based on the exploitation of a particular type of reaction catalyzed by lipases. An attempt will be made to cover as large a number of references as possible, so as to further underline the importance and significance of lipase action for industry.

Applications of lipase

(1985). Present and Future Applications of Lipases. Biotechnology and Genetic Engineering Reviews: Vol. 3, No. 1, pp. 193-218.

https://www.tandfonline.com/doi/pdf/10.1080/02648725.1985.10647813

R. C. Hammond

Papers

Present and future applications of lipases