Degradation of Phthalate Esters by Fusarium sp. DMT-5-3 and Trichosporon sp. DMI-5-1 Isolated from Mangrove Sediments

Abstract

Phthalate esters (PAEs) are important industrial compounds mainly used as plasticizers to increase flexibility and softness of plastic products. PAEs are of major concern because of their widespread use, ubiquity in the environment, and endocrine-disrupting toxicity. In this study, two fungal strains, Fusarium sp. DMT-5-3 and Trichosporon sp. DMI-5-1 which had the capability to degrade dimethyl phthalate esters (DMPEs), were isolated from mangrove sediments in the Futian Nature Reserve of Shenzhen, China, by enrichment culture technique. These fungi were identified on the basis of spore morphology and molecular typing using 18S rDNA sequence. Comparative investigations on the biodegradation of three isomers of DMPEs, namely dimethyl phthalate (DMP), dimethyl isophthalate (DMI), and dimethyl terephthalate (DMT), were carried out with these two fungi. It was found that both fungi could not completely mineralize DMPEs but transform them to the respective monomethyl phthalate or phthalate acid. Biochemical degradation pathways for different DMPE isomers by both fungi were different. Both fungi could transform DMT to monomethyl terephthalate (MMT) and further to terephthalic acid (TA) by stepwise hydrolysis of two ester bonds. However, they could only carry out one-step ester hydrolysis to transform DMI to monomethyl isophthalate (MMI). Further metabolism of MMI did not proceed. Only Trichosporon sp. was able to transform DMP to monomethyl phthalate (MMP) but not Fusarium sp. The optimal pH for DMI and DMT degradation by Fusarium sp. was 6.0 and 4.5, respectively, whereas for Trichosporon sp., the optimal pH for the degradation of all the three DMPE isomers was at 6.0. These results suggest that the fungal esterases responsible for hydrolysis of the two ester bonds of PAEs are highly substrate specific.

Degradation of di(2-ethyl hexyl) phthalate by Fusarium culmorum: Kinetics, enzymatic activities and biodegradation pathway based on quantum chemical modelingpathway based on quantum chemical modeling

“…Several studies have reported that Pleurotus ostreatus, Polyporus brumalis, Trametes versicolor, and Phlebia tremellosa are able to biodegrade diesters of phthalic acid. However, due to the slow growth of these organisms, the compounds are degraded at very slow rates (Hwang et al, 2008;Kim et al, 2008;Kim and Song, 2009;Hwang et al, 2012;Luo et al, 2012). Some ascomycete fungi from the genus Fusarium have been reported to be highly efficient phthalate-degrading organisms due to their secretion of enzymes such as esterase and laccase (Kim et al, 2007;Obruca et al, 2012;Pradeep and Benjamin, 2012;Chhaya and Gupte, 2013;Aguilar-Alvarado et al, 2015;Bouchiat et al, 2015).…”

Biotransformation of Phthalate Plasticizers and Bisphenol A by Marine-Derived, Freshwater, and Terrestrial Fungi

“…To our knowledge, previous research aiming at fungal PE metabolism has either solely emphasized hydrolytic deesterification as the primary step (Kim et al, 2003Ahn et al, 2006;Luo et al, 2011Luo et al, , 2012Hwang et al, 2012;Ahuactzin-Perez et al, 2016, or did not further elucidate the mechanisms of the suggested primary de-esterification step(s) (i.e. hydrolysis or oxidative O-dealkylation) (Lee et al, 2007).…”

“…Comparatively, fungal PE degradation has received less attention. This statement is particularly applicable to filamentous fungi dwelling within aquatic environments and also yeasts, with previous fungal based studies predominantly focusing on terrestrial ligninolytic and non-ligninolytic species (Liang et al, 2008;Luo et al, 2012;Gao and Wen, 2016;Pezzella et al, 2017). A few studies describe fungal growth on di-2-ethylhexyl phthalate (DEHP) and dimethyl phthalate esters (DMPEs) when present as the sole carbon and energy source (Luo et al, 2011;Pradeep and Benjamin, 2012).…”

“…A few studies describe fungal growth on di-2-ethylhexyl phthalate (DEHP) and dimethyl phthalate esters (DMPEs) when present as the sole carbon and energy source (Luo et al, 2011;Pradeep and Benjamin, 2012). Nevertheless, the majority of the corresponding reports point to a predominance of cometabolic PE biotransformation in fungi (Gartshore et al, 2003;Lee et al, 2007;Hwang et al, 2012;Luo et al, 2012;Ahuactzin-Perez et al, 2016;Ahuactzin-Perez et al, 2018).…”

Bioprospection of bacteria and yeasts from Atlantic Rainforest soil capable of growing in crude-glycerol residues

“…Our yeast isolates aligned with maximal identity to accessions of Trichosporon moniliiforme and Meyerozyma (ex Pichia) guilliermondii species (Table 2). T. moniliiforme has been isolated from several soil and water samples, including mangrove sediments, showing ability for bioremediation of xenobiotics (Luo et al, 2012). Antifungal activity of industrial interest for the production of bread has been reported for strains of M. guilliermondii (Coda et al, 2013), as well as biological control of fungal diseases during the post-harvest of important agricultural crops (Janisiewicz and Korsten, 2002).…”