02604nas a2200253 4500008004100000022001400041245018200055210006900237260005700306300001200363490000700375520164900382653001602031653002202047653001602069653001202085653002902097100002402126700001402150700001302164700001602177700002602193856013102219 2013 eng d a0175-759800aCombinatorial approach of statistical optimization and mutagenesis for improved production of acidic phytase by Aspergillus niger NCIM 563 under submerged fermentation condition0 aCombinatorial approach of statistical optimization and mutagenes a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcJAN a673-6790 v973 a

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.

10aAnimal feed10aAspergillus niger10aMutagenesis10aPhytase10aStatistical optimization1 aBhavsar, Kavita, P.1 aGujar, P.1 aShah, P.1 aKumar, Ravi1 aKhire, Jayant, Malhar uhttp://library.ncl.res.in/content/combinatorial-approach-statistical-optimization-and-mutagenesis-improved-production-acidic-002337nas a2200157 4500008004100000022001400041245007000055210006900125260011000194300001600304490000600320520170000326100002402026700002602050856010302076 2014 eng d a2046-206900aCurrent research and future perspectives of phytase bioprocessing0 aCurrent research and future perspectives of phytase bioprocessin aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY a26677-266910 v43 a

Phosphorus is one of nature's paradoxes as it is life's bottleneck for subsistence on earth but at same time is detrimental in surplus quantities in an aquatic environment. Phosphorus cannot be manufactured, though fortunately it can be recovered and reused. The only way to avert a supply crisis is to implement the ``3R's'' of sustainability, ``Reduce, Reuse and Recycle.'' Phytase is likely to play a critical role in the dephosphorylation of antinutritional and indigestible phytate, a phosphorus locking molecule, to digestible phosphorus, calcium and other mineral nutrients in the coming years. Hence, efforts are required to produce cost effective phytase with fast upstream and economic downstream processing because the current available process is expensive and time consuming. This review summarizes the present state of methods studied for phytase bioprocessing. Production, extraction and purification incur a large cost in product development. In addition, the process has several limitations such as dilute concentration of enzyme, extensive downstream procedures and treatment of generated effluents. However, these methods are currently employed due to lack of alternative methods. Thus, there is a clear need for an efficient, scalable and economical process for phytase production and bioseparation, and improvements are especially required with regard to yield, purity, and energy consumption. Perspectives for an improved bioprocess development for phytase are discussed based on our own experience and recent studies. It is argued that the optimization of production techniques, strain improvement and liquid-liquid extraction deserves more attention in the future.

1 aBhavsar, Kavita, P.1 aKhire, Jayant, Malhar uhttp://library.ncl.res.in/content/current-research-and-future-perspectives-phytase-bioprocessing-002000nas a2200217 4500008004100000022001400041245008000055210006900135260011000204300001600314490000700330520117500337100001801512700002201530700002201552700002401574700002601598700002801624700001801652856011201670 2015 eng d a1463-907600aCharge-switchable gold nanoparticles for enhanced enzymatic thermostability0 aChargeswitchable gold nanoparticles for enhanced enzymatic therm aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUL a21517-215240 v173 a

This study illustrates a facile strategy for efficient immobilization of enzymes on a metal nanoparticle surface. The strategy proposed here enables the enzymatic activity to be retained while increasing the enzyme thermostability. It is demonstrated that the use of a zwitterionic amino acid tyrosine as a reducing and capping agent to synthesise gold nanoparticles allows efficient immobilization of phytase enzyme through charge-switchable electrostatic interactions. The detailed kinetic and thermodynamic studies reveal that the proposed enzyme immobilization strategy improves the overall quality of phytase by reducing the activation energy required for substrate hydrolysis and broadening the temperature window in which immobilized enzyme is able to operate. The outcomes of this study indicate that the underlying zwitterionic nature of 20 natural amino acids along with significant variability in their isoelectric points and hydropathy indices as well the ability of some of the amino acids to reduce metal ions is likely to offer significant opportunities for tailoring nano-bio interfaces in a rational manner for a range of biological applications.

1 aShankar, Shiv1 aSoni, Sarvesh, K.1 aDaima, Hemant, K.1 aSelvakannan, P., R.1 aKhire, Jayant, Malhar1 aBhargava, Suresh, Kumar1 aBansal, Vipul uhttp://library.ncl.res.in/content/charge-switchable-gold-nanoparticles-enhanced-enzymatic-thermostability-0