Tyrosinase mediated humic substances synthesis by Bacillus aryabhattai TFG5

The present investigation aims at understanding the mechanism of Humic Substances (HS) formation and enhancement through tyrosinase produced by Bacillus aryabhattai TFG5. A bacterium isolated from termite mound produced tyrosinase (1.34 U.ml −1 ) and laccase (2.1 U.ml −1 ) at 48 and 60 h of fermentation respectively. The protein from B. aryabhattai TFG5 was designated as TyrB and it had a predicted molecular weight of 35.23 kDa. Swiss modelling of protein revealed a bi copper protein with its conserved residues required for activity. Interestingly, TyrB efficiently transformed and polymerized standard phenols besides transforming free phenols of Coir pith Wash Water (CWW). In addition, spectroscopic evidences suggest that TyrB enhanced the HS production from coir pith biomass. Furthermore, degradative products and changes in biomass structure by TyrB analysed through FT-IR suggests that TyrB might follow the polyphenol theory of HS synthesis.