Statistical optimization of thermo-tolerant xylanase activity from Amazon isolated Bacillus circulans on solid-state cultivation.
A 2(2) factorial design was performed to find the best conditions of pH and temperature for xylanolytic activity of Bacillus circulans BL53 isolated from the Amazon environment. Solid-state cultivation was carried out on an inexpensive, abundant agro-industrial soybean residue. The central composite design (CCD) used for the analysis of treatment combinations showed that a second-order polynomial regression model was in good agreement with experimental results, with R(2) = 0.9369 (P < 0.05). The maximum activity was obtained at a high temperature (80 degrees C) and over a large pH range (4.0-7.0). Enzymatic activity was maintained in heated extracts up to 50 degrees C, suggesting that the xylanases of B. circulans BL53 are thermo-tolerant biocatalysts, being of interest for industrial processes. The crude enzyme extract hydrolyzed rice straw, sugar cane bagasse and soybean fiber and its activity was stimulated by Co(2+), Fe(3+), and beta-mercaptoethanol but inhibited by Mn(2+), Cu(2+), Ca(2+), Zn(2+), Ba(2+), Mg(2+) and by EDTA.
Heck
Júlio Xandro
JX
Food Science and Technology Institute, Federal University of Rio Grande do Sul State, Porto Alegre, RS, Brazil.
Flôres
Simone Hickmann
SH
Hertz
Plinho Francisco
PF
Ayub
Marco Antônio Záchia
MA
D001407:Bacillus / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification*; D001431:Bacteriological Techniques; D001938:Brazil; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods*; D013025:Glycine max; D013223:Statistics as Topic; D013696:Temperature
D043364:Endo-1,4-beta Xylanases