Highly thermo–halo–alkali-stable β-1,4-endoxylanase from a novel polyextremophilic strain of Bacillus halodurans

Abstract

A novel bacterial isolate, capable of producing extracellular highly thermostable, halo-alkali-stable and cellulase-free xylanase, was isolated from soil and identified as Bacillus halodurans TSPV1 by polyphasic approach. The Plackett-Burman design identified wheat bran, lactose, tryptone and NaCl as the factors that significantly affect xylanase production, and thus, these were optimized by response surface methodology. The data analysis suggested that optimum levels of wheat bran (15-20 g L(-1)), lactose (1.0-1.5 g L(-1)), tryptone (2-2.5 g L(-1)) and NaCl (7.0-8.0 g L(-1)) support 6.75-fold higher xylanase production than that in the un-optimized medium. The xylanase is optimally active at 90 °C and pH 10, and stable for 4 h at 90 °C (T 1/2 60 h) over a broad range of NaCl concentrations (0-29 %). This is the first report on the isolation of polyextremophilic B. halodurans strain that produces thermo-halo-alkali-stable xylanase in submerged fermentation. This enzyme efficiently saccharifies agro residues like wheat bran and corncobs. Fifty-six percent of hemicellulose of wheat bran could be hydrolyzed by xylanase (100 U g(-1) substrate) along with cellulase (22 U FPase and 50 U CMCase g(-1)). The xylanase, being thermo-alkali stable and cellulase free, can find applications in pre-bleaching of paper pulps and hydrolysis of xylan in agricultural residues.

Secretion of recombinant thermo-alkali-stable endoxylanase of polyextremophilic Bacillus halodurans TSEV1 and its utility in generating xylooligosaccharides from renewable agro-residues

“…Bacillus halodurans TSEV1, a polyextremophilic bacterium, is capable of biomass degradation and a good source of endoxylanase [16,17]. The bacterium produces a high titre of cellulase-free and thermo-alkali-stable endoxylanase that finds application in generating XOs from agro-residues and in pre-bleaching of kraft pulp [16,18].…”

Optimization of the xylanase production with the newly isolated Bacillus aerophilus KGJ2

“…This will disrupt the fungal biomass and results in reduction in xylanase titers [12]. Recently many efforts had been devoted for the production of xylanases from microorganisms isolated from industrial effluents, because these organisms may produce thermostable, acidophilic and or alkaliphilic enzymes [13]. In this paper, a novel xylanase from Bacillus aerophilus KGJ2, from paper mill effluent was isolated.…”

Purificação, caracterização bioquímica e potencial de aplicação biotecnológica de uma xilanase halotolerante e termoestável de <i>Colletotrichum graminicola</i>

“…25). Um comportamento similar foi descrito para as xilanases purificadas de Bacillus subtilis (KHANDEPARKER et al, 2011) e Bacillus haludorans (KUMAR, V. et al, 2013b;PRAKASH et al, 2012). A interação com a água é crucial para a manutenção da estrutura nativa, da atividade biológica e da solubilidade das proteínas, e em altas concentrações salinas a maioria das enzimas conhecidas é inativa (KARAN et al, 2012;FANG, C. et al, 2015).…”

“…Somado a isso, os íons promovem um desarranjo das capas organizadas de moléculas de água no entorno das regiões hidrofóbicas da superfície proteica, bem como perturbações das interações eletrostáticas entre grupos carregados adjacentes (KARAN et al, 2012;FANG, C. et al, 2015). KHANDEPARKER et al, 2011;PRAKASH et al, 2012;KUMAR, V. et al, 2013b;KUMAR e SATYANARAYANA, 2014;ZHOU, J. et al, 2014;HUANG, X. et al, 2015).…”

“…31), uma vez que em ambas as concentrações do sal testadas (0,5 mol.L -1 e 2,5 mol.L -1 ) a estabilidade da enzima foi prejudicada apenas na faixa de pH de 3,0 a 3,5, quando comparada àquela observada na ausência de sal. (BAI et al, 2012;PRAKASH et al, 2012;KUMAR, V. et al, 2013b; KUMAR e SATYANARAYANA, 2014). Na ausência de NaCl a estimulação da atividade pelo substrato seguiu cinética Michaeliana e os parâmetros cinéticos determinados foram K M = 3,7 ± 0,3 mg.mL -1 e V max = 481,3 ± 34,0 U.mg -1 , resultando numa eficiência catalítica de 36,9 ± 1,5 mL.s -1 .mg -1 .…”