02267nas a2200229   4500008004100000022001400041245010000055210006900155260005700224300001200281490000700293520143300300653003201733653001401765653003001779653002601809653001701835100001901852700001701871700002601888856012301914       2010                        eng d  a0046-899100aLipase of aspergillus niger NCIM 1207: a potential biocatalyst for synthesis of isoamyl acetate0 aLipase of aspergillus niger NCIM 1207 a potential biocatalyst fo  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcOCT  a432-4370 v503 a<p>Commercial lipase preparations and mycelium bound lipase from Aspergillus niger NCIM 1207 were used for esterification of acetic acid with isoamyl alcohol to obtain isoamyl acetate. The esterification reaction was carried out at 30 degrees C in n-hexane with shaking at 120 rpm. Initial reaction rates, conversion efficiency and isoamyl acetate concentration obtained using Novozyme 435 were the highest. Mycelium bound lipase of A. niger NCIM 1207 produced maximal isoamyl acetate formation at an alcohol/acid ratio of 1.6. Acetic acid at higher concentrations than required for the critical alcohol/acid ratio lower than 1.3 and higher than 1.6 resulted in decreased yields of isoamyl acetate probably owing to lowering of micro-aqueous environmental pH around the enzyme leading to inhibition of enzyme activity. Mycelium bound A. niger lipase produced 80 g/l of isoamyl acetate within 96 h even though extremely less amount of enzyme activity was used for esterification. The presence of sodium sulphate during esterification reaction at higher substrate concentration resulted in increased conversion efficiency when we used mycelium bound enzyme preparations of A. niger NCIM 1207. This could be due to removal of excess water released during esterification reaction by sodium sulphate. High ester concentration (286.5 g/l) and conversion (73.5%) were obtained within 24 h using Novozyme 435 under these conditions.</p>10aAspergillus niger NCIM 120710aFusel oil10aIsoamyl acetate formation10aMycelium bound lipase10aNovozyme 4351 aMhetras, Nutan1 aPatil, Sonal1 aGokhale, Digambar, V.  uhttp://library.ncl.res.in/content/lipase-aspergillus-niger-ncim-1207-potential-biocatalyst-synthesis-isoamyl-acetate-002401nas a2200205   4500008004100000022001400041245011800055210006900173260010200242300001400344490000600358520153300364653003201897653003201929653003101961100001901992700003002011700002602041856012802067       2011                        eng d  a1930-212600aHyper-production of beta-glucosidase and beta-xylosidase by aspergillus niger NCIM 1207 In Xylan-Containing Media0 aHyperproduction of betaglucosidase and betaxylosidase by aspergi  aCAMPUS BOX 8005, RALEIGH, NC 27695-8005 USAbNORTH CAROLINA STATE UNIV DEPT WOOD & PAPER SCIcJAN  a2066-20760 v63 a<p>Aspergillus niger NCIM 1207 produced significantly high levels of beta-glucosidase and beta-xylosidase activities in submerged fermentation. Cellulose induced only beta-glucosidase, while xylan induced both beta-glucosidase and beta-xylosidase activities. Both the enzymes of this strain were found to undergo catabolite repression in the presence of high concentrations of glucose and glycerol. The sudden drop in pH of the fermentation medium below 3.5 caused the inactivation of enzymes when the fungus was grown in glycerol-containing media at lower temperatures. The growth of the organism at 36 degrees C led to an increase in pH of the fermentation above 6.0 that affected beta-xylosidase activity significantly. Highest levels of beta-glucosidase ((19 IU mL(-1) or 633 IU g(-1) of substrate) and beta-xylosidase (18.7 IU/mL(-1) or 620 IU g(-1) of substrate) activities were detected when A. niger was grown at 30 degrees C for first five days followed by further incubation at 36 degrees C. Such a process of growing the organism at lower temperatures (growth phase) followed by producing the enzymes at higher temperatures (production phase) in case of fungal systems has not been reported so far. The zymogram staining of the beta-glucosidase demonstrated that A. niger produced only single species of beta-glucosidase. We feel that A. niger NCIM 1207 is a potential candidate to produce both beta-glucosidase and beta-xylosidase in high amounts that can be used to supplement commercial cellulase preparations.</p>10aAspergillus niger NCIM 120710abeta-glucosidase production10abeta-xylosidase production1 aKhisti, Ujwala1 aBastawade, Kulbhushan, B.1 aGokhale, Digambar, V.  uhttp://library.ncl.res.in/content/hyper-production-beta-glucosidase-and-beta-xylosidase-aspergillus-niger-ncim-1207-xylan-0