title: Production of feed enzymes (phytase and plant cell wall hydrolyzing enzymes) by Mucor indicus MTCC 6333: purification and characterization of phytase.
abstract: The production of phytase and associated feed enzymes (phosphatase, xylanase, CMCase, alpha-amylase and beta-glucosidase) was determined in a thermotolerant fungus Mucor indicus MTCC 6333, isolated from composting soil. Solid-substrate culturing on wheat bran and optimizing other culture conditions (C and N sources, level of N, temperature, pH, culture age, inoculum level), increased the yield of phytase from 266 +/- 0.2 to 513 +/- 0.4 nkat/g substrate dry mass. The culture extract also contained 112, 194, 171, 396, and 333 nkat/g substrate of phosphatase, xylanase, CMCase, beta-glucosidase and alpha-amylase activities, respectively. Simple 2-step purification employing anion exchange and gel filtration chromatography resulted in 21.9-fold purified phytase. The optimum pH and temperature were pH 6.0 and 70 degrees C, respectively. The phytase was thermostable under acidic conditions, showing 82% residual activity after exposure to 60 degrees C at pH 3.0 and 5.0 for 2 h, and displayed broad substrate specificity. The Km was 200 nmol/L and v(lim) of 113 nmol/s per mg protein with dodecasodium phytate as substrate. In vitro feed trial with feed enzyme resulted in the release of 1.68 g inorganic P/kg of feed after 6 h of incubation at 37 degrees C.
authors.affiliation: Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, India.
authors.forename: H K
authors.initials: HK
authors.lastname: Gulati
authors.forename: B S
authors.initials: BS
authors.lastname: Chadha
authors.forename: H S
authors.initials: HS
authors.lastname: Saini
mesh_terms: D010832:6-Phytase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D000821:Animal Feed; D002473:Cell Wall / Q000378:metabolism*; D002480:Cellulase / Q000378:metabolism; D002850:Chromatography, Gel; D003470:Culture Media / Q000737:chemistry; D004043:Dietary Fiber / Q000382:microbiology; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D004795:Enzyme Stability; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000378:metabolism*; D007218:Industrial Microbiology; D009089:Mucor / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D013379:Substrate Specificity; D013696:Temperature; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D003470:Culture Media; D004043:Dietary Fiber; D006867:Hydrolases; D010832:6-Phytase; D000516:alpha-Amylases; D002480:Cellulase; C019826:carboxymethylcellulase; D043364:Endo-1,4-beta Xylanases