Unwrapping the hydrolytic system of the phytopathogenic fungus Phoma exigua by secretome analysis

作者：Tiwari Rameshwar; Singh Surender; Singh Nirpendra; Adak Anurup; Rana Sarika; Sharma Anamika; Arora Anju; Nain Lata^*

来源：Process Biochemistry, 2014, 49(10): 1630-1636.

DOI：10.1016/j.procbio.2014.06.023

• Phoma exigua
• Secretome
• Glycosyl hydrolase
• Biomass hydrolysis

The present work describes the secretome profiling of a phytopathogenic fungus, Phoma exigua by liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) based proteomics approach to highlight the suites of enzymes responsible for biomass hydrolysis. Mass spectrometry identified 33 proteins in the Phoma secretome when grown on alpha-cellulose as the sole carbon source. The functional classification revealed a unique extracellular enzyme system mainly belonging to the family of glycosyl hydrolase proteins (52%). This hydrolytic system consisted of cellulases (endo-1,4-beta-glucanase, cellobiohydrolase I, exoglucanase, and beta-glucosidase), hemicellulases (1,4-beta-xylosidase and endo-1,4-beta-xylanase) and other hypothetical proteins including GH3, GH5, GH6, GH7,GH11, GH20, GH32 and GH54. The synergistic action of this enzyme cocktail was assessed by the saccharification of alkali treated wheat straw. Since the Phoma secretome has limited beta-glucosidase activity, it was supplemented with commercial beta-glucosidase. After supplementation, this enzyme complex resulted in high yields of glucose (177.2 +/- 1.0 mg/gds), xylose (209.2 +/- 1.5 mg/gds) and arabinose (25.2 +/- 0.3 mg/gds). The secretome analysis and biomass hydrolysis by P. exigua revealed its unique potential as a source of hydrolytic enzymes for lignocellulosic biomass hydrolysis.

• 出版日期2014-10