Kinetic and thermodynamic investigation on clavulanic acid formation and degradation during glycerol fermentation by Streptomyces DAUFPE 3060

Clavulanic acid (CA) is a potent inhibitor of β-lactamases, produced by some resistant pathogenic microorganisms, which allows efficient treatment of infectious diseases. The kinetic and thermodynamic parameters of CA production by a new isolate of Streptomyces DAUFPE 3060 and its degradation were evaluated. The effect of temperature on the system was investigated in the range 24–40 °C adopting an overall model accounting for (a) the Arrhenius-type formation of CA by fermentation, (b) the hypothetical reversible unfolding of the enzyme limiting the overall metabolism, and (c) the irreversible first-order degradation of CA. The higher rates of CA formation (kCA = 0.107 h−1) and degradation (kd = 0.062 h−1) were observed at 32 and 40 °C, respectively. The main thermodynamic parameters of the three above-hypothesized events were estimated. In particular, the activation parameters of degradation (activation energy = 39.0 kJ/mol; ΔHd*=36.5 kJ/mol; ΔSd*=−219.7 J/(mol K); ΔGd*=103.5 kJ/mol) compare reasonably well with those reported in the literature for similar system without taking into account the other two events.