Developments in industrially important thermostable enzymes: a review.

The term “alkaliphile” is used for microorganisms that grow optimally or very well at pH values above 9 but cannot grow or grow only slowly at the near-neutral pH value of 6.5. Alkaliphiles include prokaryotes, eukaryotes, and archaea. Many different taxa are represented among the alkaliphiles, and some of these have been proposed as new taxa. Alkaliphiles can be isolated from normal environments such as garden soil, although viable counts of alkaliphiles are higher in samples from alkaline environments. The cell surface may play a key role in keeping the intracellular pH value in the range between 7 and 8.5, allowing alkaliphiles to thrive in alkaline environments, although adaptation mechanisms have not yet been clarified. Alkaliphiles have made a great impact in industrial applications. Biological detergents contain alkaline enzymes, such as alkaline cellulases and/or alkaline proteases, that have been produced from alkaliphiles. The current proportion of total world enzyme production destined for the laundry detergent market exceeds 60%. Another important application is the industrial production of cyclodextrin by alkaline cyclomaltodextrin glucanotransferase. This enzyme has reduced the production cost and paved the way for cyclodextrin use in large quantities in foodstuffs, chemicals, and pharmaceuticals. It has also been reported that alkali-treated wood pulp could be biologically bleached by xylanases produced by alkaliphiles. Other applications of various aspects of alkaliphiles are also discussed.

Alkaliphiles: Some Applications of Their Products for Biotechnology

The biotechnological potential of pectinolytic enzymes from microorganisms has drawn a great deal of attention from various researchers worldwide as likely biological catalysts in a variety of industrial processes. Alkaline pectinases are among the most important industrial enzymes and are of great significance in the current biotechnological arena with wide-ranging applications in textile processing, degumming of plant bast fibers, treatment of pectic wastewaters, paper making, and coffee and tea fermentations. The present review features the potential applications and uses of microbial alkaline pectinases, the nature of pectin, and the vast range of pectinolytic enzymes that function to mineralize pectic substances present in the environment. It also emphasizes the environmentally friendly applications of microbial alkaline pectinases thereby revealing their underestimated potential. The review intends to explore the potential of these enzymes and to encourage new alkaline pectinase-based industrial technology.

Microbial alkaline pectinases and their industrial applications: a review.

A review on hydrolytic enzymes in the treatment of wastewater with high oil and grease content

Summary Over the past few years, the increasing demand for natural products in the food industry has encouraged remarkable efforts towards the development of biotechnological processes for the production of flavour compounds. The present paper reviews the recent major achievements reported in this field, with a special emphasis on the potential lying in plant cell, microbial cultures and enzyme technology for the production of a wide range of flavours. The use of solid-state fermentation as a means to improve economical feasibility of these processes is also considered.

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Production of Food Aroma Compounds: Microbial and Enzymatic Methodologies

An extracellular, thermostable, alkaline lipase was partially purified from a thermophilic Bacillus strain J 33. It was optimally active at pH 8.0 at 60°C, retaining 50% activity at 70°C for 30 min. It had native molecular mass of 45 kDa. The lipase was stable in 90% (v/v) hexane or benzene mixtures in water. It converted 66% oleic acid at 0.25 M with 0.4 M methanol in hexane to methyl oleate at 60°C in 16 h. Activity was stimulated by Mg2 (10 mM) but inhibited by EDTA (10 mM) and PMSF (10 mM). It was stable in Triton X-100, Tween 20 and Tween 80 (0.1% v/v). © Rapid Science Ltd. 1998

A novel thermostable lipase from a thermophilic Bacillus sp.: characterization and esterification studies

In the present paper a comparative account of the immobilization of a Bacillus lipase on different solid supports with different surface properties and their thermostability is presented. Immobilization enhanced the thermostability of lipase. At higher temperatures, lipase immobilized and cross-linked on a hydrophobic surface showed the maximum thermostability. The optimum temperature for immobilized lipase was 9 degrees C higher than for the free enzyme, while the pH optima were the same. The half-life of soluble lipase at 50 degrees C was calculated to be 4.5 h, while immobilized lipase did not lose any activity even after 8 h. The temperature stability (for 1 h) of immobilized enzyme was enhanced from 50 to 60 degrees C in comparison with non-immobilized enzyme. Applications of immobilized lipase for esterification are also presented.

Immobilization, stability and esterification studies of a lipase from a Bacillus sp.

A new alkalophilic Bacillus GK-8 overproduced three thermostable extracellular pectinases. The temperature optima was 60°C for all the three enzymes which retained full activity for 2 h. They had pH optima 5.4, 7.0 and 10.4 and were designated as PI, PII and PIII respectively. The half life at 80°C of PI, PII and PIII was 18 min., 12 min. and 12 min., respectively. The enzyme activity was stimulated by Mg2+, Ca2+, Zn2+, Co2+ and Mn2+ ions.

Production of constitutive, thermostable, hyper active exo-pectinase from Bacillus GK-8

Biochemical analysis of a native and proteolytic fragment of a high-molecular-weight thermostable lipase from a mesophilic Bacillus sp.

The present investigation has been carried out with the aim to produce lipase from an alkalophilic yeast species by solid state fermentation using rice and wheat brans as alternative cheap solid substrates.

Nirpjit S. Dosanjh

Papers

A novel thermostable lipase from a thermophilic Bacillus sp.: characterization and esterification studies

Immobilization, stability and esterification studies of a lipase from a Bacillus sp.

Production of constitutive, thermostable, hyper active exo-pectinase from Bacillus GK-8

Biochemical analysis of a native and proteolytic fragment of a high-molecular-weight thermostable lipase from a mesophilic Bacillus sp.

Lipase production from an alkalophilic yeast sp. by solid state fermentation