Production, optimization and characterization of esterase isolated from a new endophytic Trichoderma afroharzianum strain AUMC 16,433 and its applications in dye decolorization.

BACKGROUND AND AIM

Synthetic dyes in the textile industry pose risks to human health and environmental safety. The current study aims to examine the efficacy of a novel esterase derived from an endophyte fungus in decolorizing diverse dyes, focusing on its production, purification, optimization, and characterization.

RESULTS

Trichoderma afroharzianum AUMC16433, a novel fungal endophyte with esterase-producing ability, was first detected from the cladodes of Opuntia ficus indica by ITS-rRNA sequencing. Furthermore, several fermentation variables that augment esterase production were improved by utilising the Plackett-Burman design and RSM. Ammonium sulphate precipitation at 60% and Sephacryl S300 HR gel filtration were employed to purify the isolated esterase to a specific activity of 1372.1 U/mg with a 2.29-fold increase and a recovery of 42.87%. The enzyme's molecular weight was ascertained to be 43 kDa via SDS-PAGE. The isolated esterase revealed peak activity at 40 °C and pH 8. The kinetic characteristics of esterase were Vmax = 2.717 U/mL and Km = 3.33 mM. The half-life time was 54.4% at 50 °C after 4 h, and the enzyme still retained 14.7% of its activity after 24 h at 50 °C. Esterase decolorized several synthetic dyes used industrially, with the highest decolorization rate in malachite green after 24 h with 66%, and successfully degraded both bromothymol blue and tartrazine with 65.5% and 65.3%, respectively, in the same time frame. Crystal violet and methyl red showed moderate decolorization, with decolorization rates of 57.1% and 43.1%, respectively.

CONCLUSIONS

The esterase enzyme isolated for the first time from the new endophytic Trichoderma afroharzianum has a high dyes decolorization potential, which offers it a sustainable strategy for addressing environmental contamination issues.