Optimization of the growth of and a-amylase production by Bacillus subtilis IP 5832 in shake flask and laboratory fermenter batch cultures

Abstract

The stabilities and antioxidant action of two selected flavonoids, quercetin and rutin, dissolved in methanol and water, toward continuous UV-irradiation from three different sub-ranges (UV-A, UV-B and UV-C) were studied. The flavonoids underwent degradation (bleaching) following first-order kinetics. The bleaching rates were highly dependent on the energy input of the involved UV-photons. The antioxidant activities of the two flavonoids on UV-induced lecithin lipid peroxidation were studied by the thiobarbituric acid–malondialdehyde (TBA–MDA) test, and appeared to be also affected by the continuous UV irradiation. The energy input of the incident UV-photons again played a major governing role, but an impact of the flavonoids structures cannot be neglected.

Keywords

• flavonoids
• UV-irradiation
• antioxidant
• kinetics