Wool-degrading Bacillus isolates: extracellular protease production for microbial processing of fabrics

Abstract

Wool is a natural animal fiber commonly used in fabrics, but requires physical and chemical processing treatment for such applications. With the aim of developing new woollen textile products using environmentally friendly treatments, proteolytic bacteria were isolated from raw wool samples of Merino sheep and screened for wooldegrading activity. Two isolates were identified as Bacillus megaterium L4 and Bacillus thuringiensis L11 by 16S rRNA gene sequence analysis. Both isolates grew on a minimal medium using wool-fiber or wool-fabric as sole carbon and nitrogen sources. Bacterial growth was correlated with extracellular protease activity, and maximal protease production was in early stationary phase. The exoprotease produced by L11 was found to be a thermotolerant metalloprotease stabilized by calcium or magnesium, and had optimum activity at pH 7.0 and temperature at 40°C. During bacterial growth the wool-fiber lost weight, but it did not show changes in diameter. When wool-fabric was used instead of wool-fiber weight loss and non-shrinking was found. These are encouraging results for textile processing that should be useful for development of new textile products by direct microbial processing.A potential alternative that could be suggested from our study would be to treat wool with wool-degrading microorganisms in order to develop environmentally friendly processes.

Improvement in extracellular protease production by the marine antarctic yeast Rhodotorula mucilaginosa L7

“…Many studies have evaluated the influence of nutritional conditions, such as the effect of glucose as carbon source supplemented by meat peptone and casein peptone as nitrogen source, on fungal protease production [24,25]. However, there are several studies that have tried diverse sources of carbon and nitrogen (sucrose, starch, glucose, fructose, peptone, yeast extract, sodium nitrate, and ammonium sulfate) as well as agro-industrial by-products (soybean meal, rice bran, and wheat bran) [21,22,[26][27][28][29][30]. In addition, physicochemical parameters, such as temperature and pH, have also shown to enhance protease production by microorganisms [22,27,31,32].…”

Plants, Microorganisms and Their Metabolites in Supporting Asbestos Detoxification—A Biological Perspective in Asbestos Treatment

“…Living organisms and the substances they produce are capable of destroying all sorts of materials, ranging from wood [71][72][73] and wool [74,75] to plastics [76][77][78][79], with bacteria and fungi contributing the most to these processes. Few studies are available in the literature on using microorganisms of various species and the metabolites they produce to dispose of ACW (asbestos-containing wastes) and NOA.…”

Sustainable Textile Industry: An Overview

“…However, such methods produce hazardous chemicals that can be retained in fabrics and industrial effluents. Proteolytic enzymes have been employed to generate environmentally friendly alternative procedures for fabric manufacture [69] . Because the enzymes employed are created from bacterial or fungal species cultivated via bioengineering fermentation methods and then extracted, the economics of enzyme production and extraction are cost-effective.…”