Caulobacter crescentus β-Xylosidase II Is Highly Tolerant to Inhibitors Present in Fermentative Processes Involving Lignocellulosic Biomass

Autor: Rita de Cássia Garcia Simão, Marina Kimiko Kadowaki, Juliana Moço Corrêa, José Luiz da-Conceição Silva, Rinaldo Ferreira Gandra, Amanda Alves Silva, Luciane Sene, Alexandre Maller
Rok vydání: 2020
Předmět:
Zdroj: BioEnergy Research. 13:301-313
ISSN: 1939-1242
1939-1234
DOI: 10.1007/s12155-020-10112-z
Popis: More stable enzymes with improved properties are in constant demand for various biotechnological processes. In this work, it was found that the activity of recombinant purified β-xylosidase II (CcXynB2) from the bacterium Caulobacter crescentus is increased 62% by 5 mM KCl, likely due to the presence of K+ ions. CcXynB2 activity was measured in the presence of various compounds that have been described as inhibitors of lignocellulosic biomass hydrolysis and fermentation. CcXynB2 was found to be 61% more tolerant than 200 mM ethanol over a 48-h incubation at 37 °C. The specific activity of CcXynB2 was determined in the presence of phenol, hydroxymethylfurfural, ferulic, acetic, and coumaric acids; arabinose, glucose, xylose, and pectin. After 48 h, CcXynB2 activity in the presence of these compounds was found to be equal to 100% or higher than CcXynB2 activity in the absence of these compounds. When inhibitors were used in combination, CcXynB2 retained 67% of its initial activity over 48 h at 37 °C. Enzymatic hydrolysis of hemicellulose from corncobs was performed with CcXynB2 alone or with CcXynB2 in conjunction with recombinant xylanase and β-glucosidase-β-xylosidase-α-arabinosidase from C. crescentus producing reducing sugars. The immobilized CcXynB2 was more active than the soluble enzyme at both temperatures tested, 37 and 50 °C. In addition, immobilized CcXynB2 retained most of the enzyme activity incubated at 50 °C than at 37 °C, maintaining more than 70% of its initial activity after 1 h of incubation. In general, the CCXynB2 has potential to be applied in a bioprocess since it showed robust resistance in presence of many chemical compounds that may be generated during fermentation steps and physicochemical pre-treatment of biomass if considering a simultaneous saccharification fermentation process in a biorefinery.
Databáze: OpenAIRE
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