Soil Peroxidase-Mediated Chlorination of Fulvic Acid

• Humic matter has recently been shown to contain considerable quantities of naturally produced organohalogens. The present study investigated the possibility of a non-specific, enzymatically mediated halogenation of organic matter in soil. The results showed that, in the presence of chloride and hydrogen peroxide, the enzyme chloroperox1dase (CPO) from the fungus Caldariomyces fumago catalyzes chlorination of fulvic acid. At pH 2.5 - 6.0, the chlorine to fulvic acid ratio in the tested sample was elevated from 12 mg/g to approximately 40-50 mg/g. It was also shown that this reaction can take place at chloride and hydrogen peroxide concentrations found in the environment. An extract from spruce forest soil was shown to have a measurable chlorinating capacity. The activity of an extract of 0.5 kg soil corresponded to approximately 0.3 enzyme units, measured as CPO activity. Enzymatically mediated halogenation of humic substances may be one of the mechanisms explaining the w1despread occurrence of adsorbable organic halogens (AOX) in soil and water.

Ämnesord

LANTBRUKSVETENSKAPER  -- Annan lantbruksvetenskap -- Miljö- och naturvårdsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Other Agricultural Sciences -- Environmental Sciences related to Agriculture and Land-use (hsv//eng)

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Chemisty

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