Straw, biochar, and nanocarbon altered the enzymatic reaction kinetics and thermodynamic process of catalase in the black soil under continuous warming

ABSTRACT Different C influences the kinetic and thermodynamic behavior of catalase (CAT) remains unknown. The study aimed to assess the impact of three different C [straw, biochar, nanocarbon] on kinetic and thermodynamic characteristic of CAT in 5 °C ~ 45 °C. These three C-sources increased Vmax, Vmax/Km, and decreased Km, ΔG, ΔH, ΔS at different temperatures. The addition of nanocarbon induced significant changes in the soil enzymatic characteristics, resulting in the highest soil CAT-activity. After continuous-heating, the addition of three C-sources to the soil increased and then decreased the CAT-activity and its kinetic parameters and their values peaked at 15 °C or 25 °C. On the other hand, the ΔG showed decreasing and then increasing trend and ΔS gradually increased. Q 10 decreased and correlations between CAT and kinetic thermodynamic parameters were observed with increasing-temperature in three C-treatments. There was a significant correlation between soil’s physicochemical properties and soil CAT-activity and their enzymatic reaction characteristics after straw and biochar-treatments. However, an insignificant correlation was observed between the soil indexes after the nanocarbon-treatment. Thus, different C-sources could increase the soil CAT-activity by promoting the enzymatic reaction process under continuous-warming. The continues-warming without any change in the temperature-adaptation of CAT, but its temperature-sensitivity decreased after C-source addition.