The metabolome of Sphingobium chinhatense IP26 exposed to chlorinated paraffins – Efficient data analysis with RASER

The universe of possible chloro-paraffin (CP) structures is a complex one. Even the world of short-chain CPs (SCCPs) is large, containing thousands of constitutional isomers and stereoisomers. We investigated a technical SCCP mixture (Hordalub 80, Vantage Leuna, m_Cl = 56%) and found 33 CP-homologues in this material with carbon- (n_C) and chlorine-numbers (n_Cl) varying from 10 to 13 and 4-12, respectively. In addition, 27 chloro-olefins (COs) and 18 chloro-diolefins (CdiOs) could be detected with high-resolution mass spectrometry (HRMS, R > 100'000). Respective mass spectra were processed with the R-based automated spectra evaluation routine (RASER). The SCCP mixture was then exposed to Sphingobium chinhatense IP26, which have been isolated and cultivated from a strain found in a chemical dumpsite in Chinhat, Lucknow, India. After exposure for 6 days, additional signals corresponding to hydroxylated and olefinic metabolites were observed in respective mass spectra. RASER was adapted to identify and read-out these metabolite signals too. S. chinhatense expressed the enzymes LinA and LinB. LinA, a dehydrohalogenase (17.3 kDa), is catalyzing the elimination of HCl, converting paraffinic to olefinic material (C(H)-C(X) to CC). LinB, a dehalohydroxylase (32 kDa), transforms halides to alcohols (C-X to C-OH). Both enzymes were active and we identified 9 different metabolite classes. We found mono- (CP-ols), di- (CP-diols), tri- (CP-triols) and some tetra-hydroxylated CPs (CP-tetraols). In addition to the chloro-olefins and chloro-diolefins, we also observed mono- (CO-ols) and di-hydroxylated olefins (CO-diols) and hydroxylated diolefins (CdiO-ols). In other words, the exposure of 33 SCCP homologues to S. chinhatense resulted in a metabolome with 176 metabolites including 27 COs, 18 CdiOs, 72 mono-to tetra-hydroxylated CPs, 23 CO-ols and 19 CO-diols and 17 CdiO-ols. The qualitative characterization based on HR-MS and chromatographic retention times confirmed the formation of these phase-I metabolites, which can now be searched for in other materials and environmental samples.