A novel thermostable xylanase from Geobacillus vulcani GS90: Production, biochemical characterization, and its comparative application in fruit juice enrichment.

Xylanases have great attention to act as a potential role in agro-industrial processes. In this study, production, characterization, and fruit juice application of novel xylanase from thermophilic Geobacillus vulcani GS90 (GvXyl) were performed. GvXyl was purified via acetone precipitation and gel-filtration chromatography. The results showed that GvXyl had 1,671.4 U/mg of specific activity and optimally worked at pH 8 and 55°C. It was also active in a wide pH (3-9) and temperature (30-90ºC) ranges. GvXyl was highly stable at 90ºC and relatively stable at pH 3-9. The kinetic parameters of GvXyl were obtained as K , V , and k ; 10.2 mg/ml, 4,104 µmol min  mg , and 3,542.6 s , respectively. GvXyl had higher action than commercial xylanase in fruit juice enrichment. These results revealed that GvXyl might possess a potential influence in fruit juice processing because of its high specific activity and great thermal stability. PRACTICAL APPLICATIONS: Polysaccharides include starch, pectin, and hemicellulose create problems by lowering fruit juice quality in beverages. To overcome this problem, various clarification processes might be applied to natural fruit juices. Even though chemicals are widely used for this purpose, recently enzymes including xylanases are preferred for obtaining high-quality products. In this study, we reported the production and biochemical characterization of novel thermostable xylanase from thermophilic G. vulcani GS90 (GvXyl). Also, apple and orange juice enrichment were performed with the novel xylanase to increase the quality in terms of yield, clarity, and reducing sugar substance. The improved quality features of apple and orange juices with GvXyl was then compared to commercially available β-1,4-xylanase. The results revealed that GvXyl might possess a potential influence in fruit juice processing because of its high specific activity and great thermal stability.