Biocatalytic properties of a peroxidase-active cell-free extract from onion solid wastes: caffeic acid oxidation

Abstract

The exploitation of food residual sources consists of a major factor in reducing the polluting load of food industry wastes and developing novel added-value products. Plant food residues including trimmings and peels might contain a range of enzymes capable of transforming bio-organic molecules with potential phytotoxicity, including hydrolases, peroxidases and polyphenoloxidases. Although the use of bacterial and fungal enzymes has gained interest in studies pertaining to bioremediation applications, plant enzymes have been given less attention or even disregarded. In this view, this study aimed at the investigating the use of a crude peroxidase preparation from onion solid by-products for oxidising caffeic acid, a widespread o-diphenol, whose various derivatives may occur in food industry wastes, such as olive mill waste waters. Increased enzyme activity was observed at a pH value of 5, but considerable activity was also retained for pH up to 7. Favourable temperatures for increased activity varied between 20 degrees C and 40 degrees C, 30 degrees C being the optimal. Liquid chromatography-mass spectrometry analysis of a homogenate/H(2)O(2)-treated caffeic acid solution revealed the existence of a tetramer as major oxidation product. Based on the data generated, a putative pathway for the formation of the peroxidase-mediated caffeic acid tetramer was proposed.

Chlorogenic Acid Oxidation by a Crude Peroxidase Preparation: Biocatalytic Characteristics and Oxidation Products

“…In the case of CGA, the molar ratio found was 1.6, which is higher than those reported for structurally similar hydroxycinnamate derivatives, including hydrocaffeic acid (El Agha et al 2008a) and CA (El Agha et al 2009), where the H 2 O 2 /substrate ratios determined were 1.33 and 0.8, respectively. However, this value is lower than that reported for FA, which was 2.56 (El Agha et al 2008b).…”

“…The ability of POD to form ferulic and caffeic acid (CA) dimers has been shown using an enzyme preparation from Bupleurum salicifolium callus cultures (Luis et al 2005), but more recently, the generation of FA (El Agha et al 2008a) and hydrocaffeic acid (El Agha et al 2008b) dimers, as well as CA tetramers (El Agha et al 2009), has been possible using a POD preparation from onion solid wastes.…”

Isolation of Brazilian marine fungi capable of growing on DDD pesticide

“…Hydrogen peroxide was utilized, once it promotes the activity of peroxidases (Agha et al 2009;Osborne et al 2006).…”

“…Gc1. However, the increase in degradation in the presence of H 2 O 2 suggests the involvement of peroxidases (Agha et al 2009). Osborne et al (2006) reported that a chloroperoxidase from Caldariomyces fumago catalyzes H 2 O 2 -dependant dehalogenation reactions.…”

Phenothiazines are slowly oxidizable substrates of horseradish peroxidase

“…Низкие константы скорости окисления фенотиазинов, возможно, как в случае с NADH и аскорбиновой кислотой, в первую очередь, обусловлены тем, что их окисление пероксидом водорода, протекает по одноэлектронному механизму, аналогично окислению неорганических субстратов пероксидазы [21,22]. Поэтому при совместном окислении ОДН и различных фенотиазинов, фермент реализует различные пути переноса электрона с окисляемого субстрата, выбор которых определяется доступностью функциональных групп субстрата каналам переноса электронов на поверхности белковой глобулы.…”