@article { ISI:000294225100030, title = {High level phytase production by aspergillus niger NCIM 563 in solid state culture: response surface optimization, up-scaling, and its partial characterization}, journal = {Journal of Industrial Microbiology \& Biotechnology}, volume = {38}, number = {9}, year = {2011}, month = {SEP}, pages = {1407-1417}, publisher = {SPRINGER HEIDELBERG}, address = {TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY}, abstract = {

Phytase production by Aspergillus niger NCIM 563 was optimized by using wheat bran in solid state fermentation (SSF). An integrated statistical optimization approach involving the combination of Placket-Burman design (PBD) and Box-Behnken design (BBD) was employed. PBD was used to evaluate the effect of 11 variables related to phytase production, and five statistically significant variables, namely, glucose, dextrin, NaNO(3), distilled water, and MgSO(4)center dot 7H(2)O, were selected for further optimization studies. The levels of five variables for maximum phytase production were determined by a BBD. Phytase production improved from 50 IU/g dry moldy bran (DMB) to 154 IU/g DMB indicating 3.08-fold increase after optimization. A simultaneous reduction in fermentation time from 7 to 4 days shows a high productivity of 38,500 IU/kg/day. Scaling up the process in trays gave reproducible phytase production overcoming industrial constraints of practicability and economics. The culture extract also had 133.2, 41.58, and 310.34 IU/g DMB of xylanase, cellulase, and amylase activities, respectively. The partially purified phytase was optimally active at 55A degrees C and pH 6.0. The enzyme retained ca. 75\% activity over a wide pH range 2.0-9.5. It also released more inorganic phosphorus from soybean meal in a broad pH range from 2.5 to 6.5 under emulated gastric conditions. Molecular weight of phytase on Sephacryl S-200 was approximately 87 kDa. The K (m) and V (max) observed were 0.156 mM and 220 mu m/min/mg. The SSF phytase from A. niger NCIM 563 offers an economical production capability and its wide pH stability shows its suitability for use in poultry feed.

}, keywords = {Aspergillus niger, Phytase, Response surface optimization, Solid state fermentation, Statistical methods}, issn = {1367-5435}, doi = {10.1007/s10295-010-0926-z}, author = {Bhavsar, Kavita P. and Kumar, V. Ravi and Khire, Jayant Malhar} } @article { ISI:000309333600007, title = {Downstream processing of extracellular phytase from aspergillus niger: chromatography process vs. aqueous two phase extraction for its simultaneous partitioning and purification}, journal = {Process Biochemistry}, volume = {47}, number = {7}, year = {2012}, month = {JUL}, pages = {1066-1072}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

The application of single step aqueous two-phase extraction (ATPE) for the downstream processing of phytase from Aspergillus niger NCIM 563, produced under solid state fermentation, has been studied and compared with the traditional multi-step procedure involving salt precipitation and column chromatography. High phytase recovery (98.5\%) within a short time (3 h) and improved thermostability was attained by ATPE in comparison to 20\% recovery in 96 h by chromatography process.The ATPE method, therefore, seems to be an interesting alternative for simultaneous partitioning and purification of phytase. The influence of system parameters; such as, phase forming salts, polymer molecular weight and system pH on the partitioning behavior of phytase was evaluated. The ATPE system consisting of combination of polyethylene glycol (PEG) 6000 and 8000(10.5\%) and sodium citrate (20.5\%) resulted in one-sided partitioning of phytase in bottom phase with a purification factor of 2.5. This is the first report on phytase purification using liquid-liquid extraction and the results are likely to be beneficial in the poultry feed industry. (c) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Aspergillus niger, liquid-liquid extraction, Phytase, Polyethylene glycol, Purification}, issn = {1359-5113}, doi = {10.1016/j.procbio.2012.03.012}, author = {Bhavsar, Kavita P. and Kumar, V. Ravi and Khire, Jayant Malhar} } @article { ISI:000313651700018, title = {Combinatorial approach of statistical optimization and mutagenesis for improved production of acidic phytase by Aspergillus niger NCIM 563 under submerged fermentation condition}, journal = {Applied Microbiology and Biotechnology}, volume = {97}, number = {2}, year = {2013}, month = {JAN}, pages = {673-679}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Combination of statistical optimization and mutagenesis to isolate hypersecretory strains is studied to maximize phytase production from Aspergillus niger NCIM 563 under submerged fermentation. The overall results obtained show a remarkable 5.98-fold improvement in phytase production rates when compared to that using basal medium. Optimization of culture conditions from parent strain is studied first by the Plackett-Burman technique to evaluate the effects of 11 variables for phytase production. The results showed that glucose, MgSO4, KCl, incubation period, and MnSO4 are the most significant variables affecting enzyme production. Further optimization in these variables, using a central composite design technique, resulted in 3.74-fold increase in the yield of phytase production to 254,500 U/l when compared with the activity observed with basal media (68,000 U/l) in shake flask. Our experiments show that the phytase from A. niger NCIM 563 exhibits desirable activity in simulated gastric fluid conditions with low pH and also improved thermostability when compared to commercial phytase. The improved yield demonstrates the potential applicability of phytase enzyme as a source of phytase supplement for phosphorus nutrition and environmental protection in animal feed industry. Physical and chemical mutagenesis experiments were carried out in parallel to isolate hypersecretory mutants that could possibly further enhance the enzyme production. Using optimized media conditions of the parent strain, our results show that mutant strain A. niger NCIM 1359 increased the phytase activity by another 1.6-fold to 407,200 U/l.

}, keywords = {Animal feed, Aspergillus niger, Mutagenesis, Phytase, Statistical optimization}, issn = {0175-7598}, doi = {10.1007/s00253-012-3965-8}, author = {Bhavsar, Kavita P. and Gujar, P. and Shah, P. and Kumar, V. Ravi and Khire, Jayant Malhar} }