Topic
Xylanase
About: Xylanase is a research topic. Over the lifetime, 7099 publications have been published within this topic receiving 163793 citations.
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TL;DR: Results showed that Streptomyces actuosus A-151, isolated from northern Taiwan, produced β-xylanase when rice bran was used as the sole carbon source, and addition of xylan, shrimp and crab shell powder, and orange peel to the culture medium was found to enhance the production of x Dylanase.
92 citations
TL;DR: The yield appeared to be limited by the digestibility of commercial xylan rather than by a lack of sufficient xylanase or by ethanol toxicity, and should be applicable for the production of useful chemicals from a wide range of biomass polymers.
Abstract: A two-stage process was evaluated for the fermentation of polymeric feedstocks to ethanol by a single, genetically engineered microorganism. The truncated xylanase gene (xynZ) from the thermophilic bacterium Clostridium thermocellum was fused with the N terminus of lacZ to eliminate secretory signals. This hybrid gene was expressed at high levels in ethanologenic strains of Escherichia coli KO11 and Klebsiella oxytoca M5A1(pLOI555). Large amounts of xylanase (25 to 93 mU/mg of cell protein) accumulated as intracellular products during ethanol production. Cells containing xylanase were harvested at the end of fermentation and added to a xylan solution at 60 degrees C, thereby releasing xylanase for saccharification. After cooling, the hydrolysate was fermented to ethanol with the same organism (30 degrees C), thereby replenishing the supply of xylanase for a subsequent saccharification. Recombinant E. coli metabolized only xylose, while recombinant K. oxytoca M5A1 metabolized xylose, xylobiose, and xylotriose but not xylotetrose. Derivatives of this latter organism produced large amounts of intracellular xylosidase, and the organism is presumed to transport both xylobiose and xylotriose for intracellular hydrolysis. By using recombinant M5A1, approximately 34% of the maximal theoretical yield of ethanol was obtained from xylan by this two-stage process. The yield appeared to be limited by the digestibility of commercial xylan rather than by a lack of sufficient xylanase or by ethanol toxicity. In general form, this two-stage process, which uses a single, genetically engineered microorganism, should be applicable for the production of useful chemicals from a wide range of biomass polymers. Images
92 citations
TL;DR: Activity staining indicated that A. fumigatus AR1 produced multiple xylanase of high molecular weight ranging from 212 to 253 kDa contrasting to other two alkali-tolerant fungal xylanases, which are less than 35 kDa.
92 citations
TL;DR: The UV absorption spectrum of the compounds released by enzyme treatment, and after alkali extraction, showed a characteristic peak at 280 nm, indicating the presence of lignin in the released coloring matter.
92 citations
TL;DR: The adsorption of purified Trichoderma reesei cellulases and xylanase TrXyn11 and Aspergillus niger β-glucosidase AnCel3A was studied in enzyme mixture during hydrolysis of two pretreated lignocellulosic materials and catalytically delignified spruce, along with microcrystalline cellulose.
92 citations