Microbial lipases: At the interface of aqueous and non-aqueous media

Abstract

In recent times, biotechnological applications of microbial lipases in synthesis of many organic molecules have rapidly increased in non-aqueous media. Microbial lipases are the 'working horses' in biocatalysis and have been extensively studied when their exceptionally high stability in non-aqueous media has been discovered. Stability of lipases in organic solvents makes them commercially feasibile in the enzymatic esterification reactions. Their stability is affected by temperature, reaction medium, water concentration and by the biocatalyst's preparation. An optimization process for ester synthesis from pilot scale to industrial scale in the reaction medium is discussed. The water released during the esterification process can be controlled over a wide range and has a profound effect on the activity of the lipases. Approaches to lipase catalysis like protein engineering, directed evolution and metagenome approach were studied. This review reports the recent development in the field ofnon-aqueous microbial lipase catalysis and factors controlling the esterification/transesterification processes in organic media.

Purification and Properties of Extracellular Lipases with Transesterification Activity and 1,3-Regioselectivity from Rhizomucor miehei and Rhizopus oryzae

“…This reaction is reversible; thus, lipases also catalyze the formation of acylglycerols from glycerol and free fatty acids via esterification. Other valuable properties of most lipases are the ability of catalyzing enzymatic interesterification reactions rearranging a triglyceride molecule, and transesterification between oil compounds, alkyl or aryl esters, and alcohols [3]. Lipases can also be used to accelerate the degradation of fatty waste and polyurethane [4,5].…”

Switch of substrate specificity of hyperthermophilic acylaminoacyl peptidase by combination of protein and solvent engineering

“…Lipolytic enzymes, such as lipases and esterases, catalyze a variety of reactions, including ester hydrolysis, esterification or transesterification, and they are important biocatalysts for the synthesis and resolution of enantio-pure drug precursors for the pharmaceutical industry (Houde et al, 2004;Verma et al, 2008). Because most substrates with long acyl chain lengths are hydrophobic and sparingly soluble in water, large amounts of organic solvents are usually added to the reaction system to increase substrate solubility and catalytic efficiency (Luetz et al, 2008).…”

Protein Engineering Methods and Applications

“…A recent review on microbial lipases focused on non-aqueous microbial lipase catalysis and major factors affecting esterification/transesterification processes in organic media. Additionally, protein engineering, directed evolution, metagenomics and application of these strategies on lipase catalysis were discussed (Verma et al, 2008). Similarly, lipases from other organisms such as mammals and fishes were also reviewed (Kurtovic et al, 2009).…”

“…Screening organic solvent-tolerant bacteria or extremophiles has been preferred to isolate and improve naturally solvent-stable enzymes (Gupta & Khare, 2009;Doukyu & Ogino, 2010). Other protein engineering examples with industrially and/or pharmacologically important enzymes include studies on cholesterol oxidase (Pollegioni et al, 2009), cyclodextrin glucanotransferases (Leemhuis et al, 2010), human butyrylcholinesterase (Masson et al, 2009), microbial glucoamylases (Kumar & Satyanarayana, 2009), lipases of different origins (Akoh et al, 2004;Verma et al, 2008;Kurtovic et al, 2009), phospholipases (Song et al, 2005;De Maria et al, 2007;Simockova & Griac, 2009) and phytases (Rao et al, 2009). Studies on extremozymes, enzymes isolated from extremophilic species, revealed their different structural and functional characteristics which could be exploited for biotechnological applications and improved further by protein engineering (Bjarnason et al, 1993;Hough & Danson, 1999;Georlette et al, 2004).…”