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( Silveira Silvana T. ),( Sabrine Gemelli ),( Jeferson Segalin ),( Adriano Brandelli ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.6
Keratinases are exciting keratin-degrading enzymes; however, there have been relatively few studies on their immobilization. A keratinolytic protease from Chryseobacterium sp. kr6 was purified and its partial sequence determined using mass spectrometry. No significant homology to other microbial peptides in the NCBI database was observed. Certain parameters for immobilization of the purified keratinase on chitosan beads were investigated. The production of the chitosan beads was optimized using factorial design and surface response techniques. The optimum chitosan bead production for protease immobilization was a 20 g/l chitosan solution in acetic acid [1.5% (v/v)], glutaraldehyde ranging from 34 g to 56 g/l, and an activation time between 6 and 10 h. Under these conditions, above 80% of the enzyme was immobilized on the support. The behavior of the keratinase loading on the chitosan beads surface was well described using the Langmuir model. The maximum capacity of the support (qm) and dissociation constant (Kd) were estimated as 58.8 U/g and 0.245 U/ml, respectively. The thermal stability of the immobilized enzyme was also improved around 2-fold, when compared with that of the free enzyme, after 30 min at 65oC. In addition, the activity of the immobilized enzyme remained at 63.4% after it was reused five times. Thus, the immobilized enzyme exhibited an improved thermal stability and remained active after several uses.
Evaluation of Different Parameters for the Purification of Inulinase Using an Ion Exchange Fixed Bed
Susana J. Kalil,Silvana T. Silveira,Francisco Maugeri-Filho,Maria Isabel Rodrigues 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.4
The main conditions affecting the downstream process for purification of inulinase from Kluyveromyces marxianus var. bulgaricus ATCC 16045 were investigated. Parameters including the elution mode, linear rate, ionic strength, and elution pH were evaluated in order to achieve the best purification factor and recovery. The best purification factor and recovery were achieved in run 6 using a gradient elution mode with concentrations of NaCl ranging from 0 to 1 M, a linear flow rate of 100 cm/h and a pH value of 4.1. Under these conditions, the recovery was ~ 67.5% and the purification factor ~ 6.6-fold.