Alkaliphiles — from an industrial point of view

Abstract

Organisms with pH optima for growth in excess of pH 9 are defined as alkaliphiles (or sometimes alkalophiles). Alkaliphiles contain prokaryotes, eukaryotes, and archaea. It is clear that many different taxa are represented among the alkaliphiles, and some of them are proposed as new taxa. Alkaliphiles can b isolated from normal environments such as garden soil, although counts of the alkaliphiles are higher in alkaline environments. 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 detergents market exceeds 30%. Another important application is the industrial production of cyclodextrin with alkaline cyclomaltodextrin glucanotransferase. This enzyme reduced the production cost and paved the way for its use in large quantities in foodstuffs, chemicals and pharmaceuticals. Besides these applications, there are other possible applications in food and waste treatment industries.

Purification and characterisation of alkaline cellulase produced by a novel isolate, Bacillus sphaericus JS1

“…JS1 CMCase was active over a broad range of pH (7.0-10.5). Similar observations were also made by others [7,8,12,13,14,23,41,43,45].…”

“…are known to produce a variety of industrially important alkaline hydrolytic extracellular enzymes, such as amylases, cellulases, pectinases and proteases [12,13,16,18,19,31,37]. The potential of cellulases has been revealed in various industrial processes, including food, textiles and laundry, pulp and paper, and agriculture as well as in research and development [2,3,4,5,8,15,21,25,26,27,28,30,34,42,43,44,45].…”

A new facultatively autotrophic hydrogen- and sulfur-oxidizing bacterium from an alkaline environment

“…During the past few years, however, these environments have received more attention because of industrial needs for microbial enzymes from alkaliphilic bacteria, represented mainly by the alkaliphilic nonhalophilic Bacillus and halotolerant Halomonas species (Horikoshi 1996;Duckworth et al 1996). Recently, investigation of bacteria important in biogeochemical cycling in soda lakes has begun (Zavarzin 1993).…”

A survey of proteases in edible mushrooms with synthetic peptides as substrates

“…The enzymes are categorized into four groups, serine proteases, cysteine proteases, aspartic proteases, and metalloproteases, based on their active sites (van der Hoorn 2008). Proteases are characteristically distributed in cells and tissues, and function in such major physiological processes as protein turnover, sporulation and conidial discharge, germination, enzyme modification, nutrition, and regulation of gene expression (Horikoshi 1996). Proteases also have important applications in industry including the detergent, food, pharmaceutical, leather, and silk industries, and recovery of silver from used X-ray films (Lee et al 1991;Kembhavi et al 1993;Gessesse and Gashe 1997;Anwar and Saleemuddin 1998;Rao et al 1998).…”