Comparison of initial hydrolysis of the three dimethyl phthalate esters (DMPEs) by a basidiomycetous yeast, Trichosporon DMI-5-1, from coastal sediment

Abstract

This study shows that different catalytic processes are involved in the transformation of DMPEs by the basidiomycetous yeast Trichosporon sp. DMI-5-1 and suggests that its esterases, responsible for the initial hydrolyzing the two ester bonds of DMPEs, are highly substrate specific.

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

“…This yeast species was described to be inactive on the comparatively more hydrophobic and hence less water soluble PE dioctyl phthalate (DOP; log K ow = 7.32; Cousins and Mackay, 2000;Net et al, 2015;Sabev et al, 2006) possibly due to a lower bioavailability and/or mechanistic biochemical constraints of the degradability of DOP compared to DBP. Limited growth of Trichosporon DMI-5-1, a yeast isolate obtained from costal sediment, on different DMPEs was reported previously (Luo et al, 2011). Initial hydrolysis of DMPEs by Trichosporon DMI-5-1 led to the accumulation of aromatic products (monoesters, terephthalic acid), without their further breakdown.…”

“…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).…”

“…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). 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).…”

“…Additionally, phthalates with longer side chains than diethyl phthalate (DEP) may first undergo alkyl chain shortening via β-oxidation, a process initiated by cytochrome P450 mediated hydroxylation, prior to de-esterification occurring (Amir et al, 2005;Liang et al, 2008). Lastly, transesterification involving the introduction of shorter alkyl chains in exchange for longer ones may alternatively take place, followed by de-esterification to yield PA as a central intermediate (Jackson et al, 1996;Cartwright et al, 2000;Lee et al, 2007;Liang et al, 2008).…”

A monograph on the remediation of hazardous phthalates

“…A basidiomycetous yeast Trichosporon sp. DMI-5-1 isolated from coastal sediment could transform three DMPs, viz., DMP, DMIP and DMTP -to respective monoester or phthalic acid, but not minerealized [94].…”