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Cui Z, Li Y, Jing X, Luan X, Liu N, Liu J, Meng Y, Xu J, Valentine DL. Cycloalkane degradation by an uncultivated novel genus of Gammaproteobacteria derived from China's marginal seas. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133904. [PMID: 38422739 DOI: 10.1016/j.jhazmat.2024.133904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 01/30/2024] [Accepted: 02/25/2024] [Indexed: 03/02/2024]
Abstract
The consumption of cycloalkanes is prevalent in low-temperature marine environments, likely influenced by psychrophilic microorganisms. Despite their significance, the primary active species responsible for marine cycloalkane degradation remain largely unidentified due to cultivation challenges. In this study, we provide compelling evidence indicating that the uncultured genus C1-B045 of Gammaproteobacteria is a pivotal participant in cycloalkane decomposition within China's marginal seas. Notably, the relative abundance of C1-B045 surged from 15.9% in the methylcyclohexane (MCH)-consuming starter culture to as high as 97.5% in MCH-utilizing extinction cultures following successive dilution-to-extinction and incubation cycles. We used stable isotope probing, Raman-activated gravity-driven encapsulation, and 16 S rRNA gene sequencing to link cycloalkane-metabolizing phenotype to genotype at the single-cell level. By annotating key enzymes (e.g., alkane monooxygenase, cyclohexanone monooxygenase, and 6-hexanolactone hydrolase) involved in MCH metabolism within C1-B045's representative metagenome-assembled genome, we developed a putative MCH degradation pathway.
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Affiliation(s)
- Zhisong Cui
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China.
| | - Yingchao Li
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China
| | - Xiaoyan Jing
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Energy Institute, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, People's Republic of China
| | - Xiao Luan
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100048, People's Republic of China
| | - Na Liu
- Department of Earth Science and Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Jinyan Liu
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China
| | - Yu Meng
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Energy Institute, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, People's Republic of China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Energy Institute, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, People's Republic of China
| | - David L Valentine
- Department of Earth Science and Marine Science Institute, University of California, Santa Barbara, CA 93106, USA.
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2
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Randazzo A, Venturi S, Tassi F. Soil processes modify the composition of volatile organic compounds (VOCs) from CO 2- and CH 4-dominated geogenic and landfill gases: A comprehensive study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171483. [PMID: 38458441 DOI: 10.1016/j.scitotenv.2024.171483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/06/2024] [Accepted: 03/03/2024] [Indexed: 03/10/2024]
Abstract
Degradation mechanisms affecting non-methane volatile organic compounds (VOCs) during gas uprising from different hypogenic sources to the surface were investigated through extensive sampling surveys in areas encompassing a high enthalpy hydrothermal system associated with active volcanism, a CH4-rich sedimentary basin and a municipal waste landfill. For a comprehensive framework, published data from medium-to-high enthalpy hydrothermal systems were also included. The investigated systems were characterised by peculiar VOC suites that reflected the conditions of the genetic environments in which temperature, contents of organic matter, and gas fugacity had a major role. Differences in VOC patterns between source (gas vents and landfill gas) and soil gases indicated VOC transformations in soil. Processes acting in soil preferentially degraded high-molecular weight alkanes with respect to the low-molecular weight ones. Alkenes and cyclics roughly behaved like alkanes. Thiophenes were degraded to a larger extent with respect to alkylated benzenes, which were more reactive than benzene. Furan appeared less degraded than its alkylated homologues. Dimethylsulfoxide was generally favoured with respect to dimethylsulfide. Limonene and camphene were relatively unstable under aerobic conditions, while α-pinene was recalcitrant. O-bearing organic compounds (i.e., aldehydes, esters, ketones, alcohols, organic acids and phenol) acted as intermediate products of the ongoing VOC degradations in soil. No evidence for the degradation of halogenated compounds and benzothiazole was observed. This study pointed out how soil degradation processes reduce hypogenic VOC emissions and the important role played by physicochemical and biological parameters on the effective VOC attenuation capacity of the soil.
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Affiliation(s)
- A Randazzo
- Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Firenze, Italy; Institute of Geosciences and Earth Resources (IGG), National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Firenze, Italy.
| | - S Venturi
- Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Firenze, Italy; Institute of Geosciences and Earth Resources (IGG), National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Firenze, Italy
| | - F Tassi
- Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Firenze, Italy; Institute of Geosciences and Earth Resources (IGG), National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Firenze, Italy
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Arrington EC, Tarn J, Kittner HE, Kivenson V, Liu RM, Valentine DL. Methylated cycloalkanes fuel a novel genus in the Porticoccaceae family (Ca. Reddybacter gen. nov). Environ Microbiol 2023; 25:2958-2971. [PMID: 37599091 DOI: 10.1111/1462-2920.16474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023]
Abstract
Cycloalkanes are abundant and toxic compounds in subsurface petroleum reservoirs and their fate is important to ecosystems impacted by natural oil seeps and spills. This study focuses on the microbial metabolism of methylcyclohexane (MCH) and methylcyclopentane (MCP) in the deep Gulf of Mexico. MCH and MCP are often abundant cycloalkanes observed in petroleum and will dissolve into the water column when introduced at the seafloor via a spill or natural seep. We conducted incubations with deep Gulf of Mexico (GOM) seawater amended with MCH and MCP at four stations. Within incubations with active respiration of MCH and MCP, we found that a novel genus of bacteria belonging to the Porticoccaceae family (Candidatus Reddybacter) dominated the microbial community. Using metagenome-assembled genomes, we reconstructed the central metabolism of Candidatus Reddybacter, identifying a novel clade of the particulate hydrocarbon monooxygenase (pmo) that may play a central role in MCH and MCP metabolism. Through comparative analysis of 174 genomes, we parsed the taxonomy of the Porticoccaceae family and found evidence suggesting the acquisition of pmo and other genes related to the degradation of cyclic and branched hydrophobic compounds were likely key events in the ecology and evolution of this group of organisms.
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Affiliation(s)
- Eleanor C Arrington
- Marine Science Institute, University of California-Santa Barbara, Santa Barbara, California, USA
| | - Jonathan Tarn
- Interdepartmental Graduate Program in Marine Science, University of California-Santa Barbara, Santa Barbara, California, USA
| | - Hailie E Kittner
- Interdepartmental Graduate Program in Marine Science, University of California-Santa Barbara, Santa Barbara, California, USA
| | - Veronika Kivenson
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California, USA
| | - Rachel M Liu
- School of Oceanography, University of Washington, Seattle, Washington, USA
| | - David L Valentine
- Marine Science Institute, University of California-Santa Barbara, Santa Barbara, California, USA
- Department of Earth Science, University of California-Santa Barbara, Santa Barbara, California, USA
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4
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Li Y, Cui Z, Luan X, Bian X, Li G, Hao T, Liu J, Feng K, Song Y. Degradation potential and pathways of methylcyclohexane by bacteria derived from Antarctic surface water. CHEMOSPHERE 2023; 329:138647. [PMID: 37037356 DOI: 10.1016/j.chemosphere.2023.138647] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/06/2023] [Accepted: 04/07/2023] [Indexed: 05/03/2023]
Abstract
Cycloalkanes pose a tremendous environmental risk due to their high concentration in petroleum hydrocarbons and hazardous effects to organisms. Numerous studies have documented the biodegradation of acyclic alkanes and aromatic hydrocarbons. However, insufficient attention has been paid to studies on the microbial degradation of cycloalkanes, which might be closely linked to psychrophilic microbes derived from low-temperature habitats. Here we show that endemic methylcyclohexane (MCH, an abundant cycloalkane species in oil) consumers proliferated in seawater samples derived from the Antarctic surface water (AASW). The MCH-consuming bacterial communities derived from AASW exhibited a distinct species composition compared with their counterparts derived from other cold-water habitats. We also probed Colwellia and Roseovarius as the key active players in cycloalkane degradation by dilution-to-extinction-based incubation with MCH as sole source of carbon and energy. Furthermore, we propose two nearly complete MCH degradation pathways, lactone formation and aromatization, concurrently in the high-quality metagenome-assembled genomes of key MCH consumer Roseovarius. Overall, we revealed that these Antarctic microbes might have strong interactions that enhance the decomposition of more refractory hydrocarbons through complementary degradation pathways.
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Affiliation(s)
- Yingchao Li
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China
| | - Zhisong Cui
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, People's Republic of China.
| | - Xiao Luan
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, 100048, People's Republic of China
| | - Xinqi Bian
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China
| | - Guoqing Li
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China
| | - Tong Hao
- College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao, 266590, People's Republic of China
| | - Jinyan Liu
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China
| | - Ke Feng
- Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China
| | - Yizhi Song
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China; Division of Life Sciences and Medicine, School of Biomedical Engineering (Suzhou), University of Science and Technology of China, Suzhou, 215163, China.
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Cui Z, Luan X, Li S, Li Y, Bian X, Li G, Wei Q, Ran X, Bao M, Valentine DL. Occurrence and distribution of cyclic-alkane-consuming psychrophilic bacteria in the Yellow Sea and East China Sea. JOURNAL OF HAZARDOUS MATERIALS 2022; 427:128129. [PMID: 34991007 DOI: 10.1016/j.jhazmat.2021.128129] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/09/2021] [Accepted: 12/19/2021] [Indexed: 06/14/2023]
Abstract
Cyclic alkanes (c-alkanes) are toxic compounds that are abundant in subsurface oil reservoirs and spilled condensate; hence, their environmental risk is significant. Although numerous studies have focused on the decomposition of other compound classes, e.g., acyclic alkanes and aromatic hydrocarbons, very little is known about the biodegradation of c-alkanes in the marine environment. Here, we enriched methylcyclohexane (MCH)-degrading bacteria derived from the cold bottom water (10-20 °C) of China's marginal seas in summer and characterized the changes to the bacterial community using high-throughput amplicon sequencing. MCH-consuming bacteria failed to grow from the warmer surface water (25-29 °C) in the same geographic sites and seasons. Notably, MCH-consuming communities derived from the cold bottom water in the Yellow Sea exhibit distinct structures compared to the other treatments. Furthermore, almost all dominant species in this setting appear to be specifically adapted to deeper cold water as indicated by significantly negative correlations to temperature (P < 0.01). From these results, we proposed that the biodegradation of MCH is effectively limited to the colder waters (10-20 °C) of China's marginal seas, with uncultured psychrophiles acting as the key taxa for MCH decomposition. Overall, this study indicates key functions for uncultivated microbes in the marine environment.
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Affiliation(s)
- Zhisong Cui
- Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, People's Republic of China.
| | - Xiao Luan
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China
| | - Shujun Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, People's Republic of China
| | - Yingchao Li
- Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China
| | - Xinqi Bian
- Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China
| | - Guoqing Li
- Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China
| | - Qinsheng Wei
- Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China
| | - Xiangbin Ran
- Marine Bioresources and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, People's Republic of China
| | - Mutai Bao
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, People's Republic of China
| | - David L Valentine
- Department of Earth Science and Marine Science Institute, University of California, Santa Barbara, CA 93106, USA.
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6
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Biodegradation of naphthenic acids: identification of Rhodococcus opacus R7 genes as molecular markers for environmental monitoring and their application in slurry microcosms. Appl Microbiol Biotechnol 2020; 104:2675-2689. [PMID: 31993702 DOI: 10.1007/s00253-020-10378-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 10/30/2019] [Accepted: 01/14/2020] [Indexed: 10/25/2022]
Abstract
Nowadays, the increase of the unconventional oil deposit exploitation and the amount of oil sands process-affected waters (OSPW) in tailing ponds emerges the importance of developing bio-monitoring strategies for the restoration of these habitats. The major constituents of such deposits are naphthenic acids (NAs), emerging contaminant mixtures with toxic and recalcitrant properties. With the aim of developing bio-monitoring strategies based on culture-independent approach, we identified genes coding for enzymes involved in NA degradation from Rhodococcus opacus R7 genome, after the evaluation of its ability to mineralize model NAs. R. opacus R7 whole-genome analysis unveiled the presence of pobA and chcpca gene clusters putatively involved in NAs degradation. Gene expression analysis demonstrated the specific induction of R7 aliA1 gene, encoding for a long-chain-fatty-acid-CoA ligase, in the presence of cyclohexanecarboxylic acid (CHCA) and hexanoic acid (HA), selected as representative compounds for alicyclic and linear NAs, respectively. Therefore, aliA1 gene was selected as a molecular marker to monitor the biodegradative potential of slurry-phase sand microcosms in different conditions: spiked with CHCA, in the presence of R. opacus R7, the autochthonous microbial community, and combining these factors. Results revealed that the aliA1-targeting culture-independent approach could be a useful method for bio-monitoring of NA degradation in a model laboratory system.
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7
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Fungal biotransformation of short-chain n-alkylcycloalkanes. Appl Microbiol Biotechnol 2019; 103:4137-4151. [PMID: 30941461 DOI: 10.1007/s00253-019-09749-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/25/2019] [Accepted: 03/03/2019] [Indexed: 10/27/2022]
Abstract
The cycloalkanes, comprising up to 45% of the hydrocarbon fraction, occur in crude oil or refined oil products (e.g., gasoline) mainly as alkylated cyclohexane derivatives and have been increasingly found in environmental samples of soil and water. Furthermore, short-chain alkylated cycloalkanes are components of the so-called volatile organic compounds (VOCs). This study highlights the biotransformation of methyl- and ethylcyclohexane by the alkane-assimilating yeast Candida maltosa and the phenol- and benzoate-utilizing yeast Trichosporon mucoides under laboratory conditions. In the course of this biotransformation, we detected 25 different metabolites, which were analyzed by HPLC and GC-MS. The biotransformation process of methylcyclohexane in both yeasts involve (A) ring hydroxylation at different positions (C2, C3, and C4) and subsequent oxidation to ketones as well as (B) oxidation of the alkyl side chain to hydroxylated and acid products. The yeast T. mucoides additionally performs ring hydroxylation at the C1-position and (C) oxidative decarboxylation and (D) aromatization of cyclohexanecarboxylic acid. Both yeasts also oxidized the saturated ring system and the side chain of ethylcyclohexane. However, the cyclohexylacetic acid, which was formed, seemed not to be substrate for aromatization. This is the first report of several new transformation reactions of alkylated cycloalkanes for eukaryotic microorganisms.
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Presentato A, Cappelletti M, Sansone A, Ferreri C, Piacenza E, Demeter MA, Crognale S, Petruccioli M, Milazzo G, Fedi S, Steinbüchel A, Turner RJ, Zannoni D. Aerobic Growth of Rhodococcus aetherivorans BCP1 Using Selected Naphthenic Acids as the Sole Carbon and Energy Sources. Front Microbiol 2018; 9:672. [PMID: 29706937 PMCID: PMC5906575 DOI: 10.3389/fmicb.2018.00672] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/22/2018] [Indexed: 11/13/2022] Open
Abstract
Naphthenic acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that Rhodococcus aetherivorans BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL-1. The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability. BCP1 cell adaptation responses that allowed survival on NAs included changes in cell morphology, production of intracellular bodies and changes in fatty acid composition. Transmission electron microscopy (TEM) analysis of BCP1 cells grown on CHCA or CPCA showed a slight reduction in the cell size, the production of EPS-like material and intracellular electron-transparent and electron-dense inclusion bodies. The electron-transparent inclusions increased in the amount and size in NA-grown BCP1 cells under nitrogen limiting conditions and contained storage lipids as suggested by cell staining with the lipophilic Nile Blue A dye. Lipidomic analyses revealed significant changes with increases of methyl-branched (MBFA) and polyunsaturated fatty acids (PUFA) examining the fatty acid composition of NAs-growing BCP1 cells. PUFA biosynthesis is not usual in bacteria and, together with MBFA, can influence structural and functional processes with resulting effects on cell vitality. Finally, through the use of RT (Reverse Transcription)-qPCR, a gene cluster (chcpca) was found to be transcriptionally induced during the growth on CHCA and CPCA. Based on the expression and bioinformatics results, the predicted products of the chcpca gene cluster are proposed to be involved in aerobic NA degradation in R. aetherivorans BCP1. This study provides first insights into the genetic and metabolic mechanisms allowing a Rhodococcus strain to aerobically degrade NAs.
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Affiliation(s)
- Alessandro Presentato
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Martina Cappelletti
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Anna Sansone
- ISOF, Consiglio Nazionale delle Ricerche, Bologna, Italy
| | - Carla Ferreri
- ISOF, Consiglio Nazionale delle Ricerche, Bologna, Italy
| | - Elena Piacenza
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Marc A. Demeter
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Silvia Crognale
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Maurizio Petruccioli
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Giorgio Milazzo
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Stefano Fedi
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Alexander Steinbüchel
- Institute of Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
- Department of Environmental Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Raymond J. Turner
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Davide Zannoni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
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9
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Mikolasch A, Reinhard A, Alimbetova A, Omirbekova A, Pasler L, Schumann P, Kabisch J, Mukasheva T, Schauer F. From oil spills to barley growth - oil-degrading soil bacteria and their promoting effects. J Basic Microbiol 2016; 56:1252-1273. [PMID: 27624187 DOI: 10.1002/jobm.201600300] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/06/2016] [Indexed: 12/30/2022]
Abstract
Heavy contamination of soils by crude oil is omnipresent in areas of oil recovery and exploitation. Bioremediation by indigenous plants in cooperation with hydrocarbon degrading microorganisms is an economically and ecologically feasible means to reclaim contaminated soils. To study the effects of indigenous soil bacteria capable of utilizing oil hydrocarbons on biomass production of plants growing in oil-contaminated soils eight bacterial strains were isolated from contaminated soils in Kazakhstan and characterized for their abilities to degrade oil components. Four of them, identified as species of Gordonia and Rhodococcus turned out to be effective degraders. They produced a variety of organic acids from oil components, of which 59 were identified and 7 of them are hitherto unknown acidic oil metabolites. One of them, Rhodococcus erythropolis SBUG 2054, utilized more than 140 oil components. Inoculating barley seeds together with different combinations of these bacterial strains restored normal growth of the plants on contaminated soils, demonstrating the power of this approach for bioremediation. Furthermore, we suggest that the plant promoting effect of these bacteria is not only due to the elimination of toxic oil hydrocarbons but possibly also to the accumulation of a variety of organic acids which modulate the barley's rhizosphere environment.
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Affiliation(s)
- Annett Mikolasch
- Department of Applied Microbiology, Institute of Microbiology, University Greifswald, Greifswald, Germany
| | - Anne Reinhard
- Department of Applied Microbiology, Institute of Microbiology, University Greifswald, Greifswald, Germany
| | - Anna Alimbetova
- Department of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Anel Omirbekova
- Department of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Lisa Pasler
- Department of Applied Microbiology, Institute of Microbiology, University Greifswald, Greifswald, Germany
| | - Peter Schumann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Johannes Kabisch
- Institute of Biochemistry, University Greifswald, 17487, Greifswald, Germany
| | - Togzhan Mukasheva
- Department of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Frieder Schauer
- Department of Applied Microbiology, Institute of Microbiology, University Greifswald, Greifswald, Germany
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10
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Scherr KE, Backes D, Scarlett AG, Lantschbauer W, Nahold M. Biogeochemical gradients above a coal tar DNAPL. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 563-564:741-754. [PMID: 26610368 DOI: 10.1016/j.scitotenv.2015.11.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/06/2015] [Accepted: 11/07/2015] [Indexed: 06/05/2023]
Abstract
Naturally occurring distribution and attenuation processes can keep hydrocarbon emissions from dense non aqueous phase liquids (DNAPL) into the adjacent groundwater at a minimum. In a historically coal tar DNAPL-impacted site, the de facto absence of a plume sparked investigations regarding the character of natural attenuation and DNAPL resolubilization processes at the site. Steep vertical gradients of polycyclic aromatic hydrocarbons, microbial community composition, secondary water quality and redox-parameters were found to occur between the DNAPL-proximal and shallow waters. While methanogenic and mixed-electron acceptor conditions prevailed close to the DNAPL, aerobic conditions and very low dissolved contaminant concentrations were identified in three meters vertical distance from the phase. Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) proved to be an efficient tool to characterize the behavior of the present complex contaminant mixture. Medium to low bioavailability of ferric iron and manganese oxides of aquifer samples was detected via incubation with Shewanella alga and evidence for iron and manganese reduction was collected. In contrast, 16S rDNA phylogenetic analysis revealed the absence of common iron reducing bacteria. Aerobic hydrocarbon degraders were abundant in shallow horizons, while nitrate reducers were dominating in deeper aquifer regions, in addition to a low relative abundance of methanogenic archaea. Partial Least Squares - Canonical Correspondence Analysis (PLS-CCA) suggested that nitrate and oxygen concentrations had the greatest impact on aquifer community structure in on- and offsite wells, which had a similarly high biodiversity (H' and Chao1). Overall, slow hydrocarbon dissolution from the DNAPL appears to dominate natural attenuation processes. This site may serve as a model for developing legal and technical strategies for the treatment of DNAPL-impacted sites where contaminant plumes are absent or shrinking.
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Affiliation(s)
- Kerstin E Scherr
- University of Natural Resources and Life Sciences Vienna (BOKU), Department IFA-Tulln, Institute for Environmental Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln, Austria.
| | - Diana Backes
- University of Natural Resources and Life Sciences Vienna (BOKU), Department IFA-Tulln, Institute for Environmental Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln, Austria
| | - Alan G Scarlett
- University of Plymouth, Petroleum and Environmental Geochemistry Group, Biogeochemistry Research Centre, Drake Circus, Plymouth, Devon PL4 8AA, UK
| | - Wolfgang Lantschbauer
- Government of Upper Austria, Directorate for Environment and Water Management, Division for Environmental Protection, Kärntner Strasse 10-12, 4021 Linz, Austria
| | - Manfred Nahold
- GUT Gruppe Umwelt und Technik GmbH, Ingenieurbüro für Technischen Umweltschutz, Plesching 15, 4040 Linz, Austria
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11
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A Comprehensive Review of Aliphatic Hydrocarbon Biodegradation by Bacteria. Appl Biochem Biotechnol 2015; 176:670-99. [PMID: 25935219 DOI: 10.1007/s12010-015-1603-5] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 03/31/2015] [Indexed: 02/07/2023]
Abstract
Hydrocarbons are relatively recalcitrant compounds and are classified as high-priority pollutants. However, these compounds are slowly degraded by a large variety of microorganisms. Bacteria are able to degrade aliphatic saturated and unsaturated hydrocarbons via both aerobic and anaerobic pathways. Branched hydrocarbons and cyclic hydrocarbons are also degraded by bacteria. The aerobic bacteria use different types of oxygenases, including monooxygenase, cytochrome-dependent oxygenase and dioxygenase, to insert one or two atoms of oxygen into their targets. Anaerobic bacteria, on the other hand, employ a variety of simple organic and inorganic molecules, including sulphate, nitrate, carbonate and metals, for hydrocarbon oxidation.
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12
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Mikolasch A, Omirbekova A, Schumann P, Reinhard A, Sheikhany H, Berzhanova R, Mukasheva T, Schauer F. Enrichment of aliphatic, alicyclic and aromatic acids by oil-degrading bacteria isolated from the rhizosphere of plants growing in oil-contaminated soil from Kazakhstan. Appl Microbiol Biotechnol 2015; 99:4071-84. [PMID: 25592733 DOI: 10.1007/s00253-014-6320-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/09/2014] [Accepted: 12/12/2014] [Indexed: 10/24/2022]
Abstract
Three microbial strains were isolated from the rhizosphere of alfalfa (Medicago sativa), grass mixture (Festuca rubra, 75 %; Lolium perenne, 20 %; Poa pratensis, 10 %), and rape (Brassica napus) on the basis of their high capacity to use crude oil as the sole carbon and energy source. These isolates used an unusually wide spectrum of hydrocarbons as substrates (more than 80), including n-alkanes with chain lengths ranging from C12 to C32, monomethyl- and monoethyl-substituted alkanes (C12-C23), n-alkylcyclo alkanes with alkyl chain lengths from 4 to 18 carbon atoms, as well as substituted monoaromatic and diaromatic hydrocarbons. These three strains were identified as Gordonia rubripertincta and Rhodococcus sp. SBUG 1968. During their transformation of this wide range of hydrocarbon substrates, a very large number of aliphatic, alicyclic, and aromatic acids was detected, 44 of them were identified by GC/MS analyses, and 4 of them are described as metabolites for the first time. Inoculation of plant seeds with these highly potent bacteria had a beneficial effect on shoot and root development of plants which were grown on oil-contaminated sand.
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Affiliation(s)
- Annett Mikolasch
- Department of Applied Microbiology, Institute of Microbiology, University Greifswald, Friedrich-Ludwig-Jahn-Str. 15, 17487, Greifswald, Germany,
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13
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Seyfried M, Boschung A, Miffon F, Ohleyer E, Chaintreau A. Elucidation of the upper pathway of alicyclic musk Romandolide degradation in OECD screening tests with activated sludge. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 21:9487-9494. [PMID: 24277432 DOI: 10.1007/s11356-013-2347-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 11/04/2013] [Indexed: 06/02/2023]
Abstract
The degradation of Romandolide ([1-(3',3'-dimethyl-1'-cyclohexyl)ethoxycarbonyl] methyl propanoate), a synthetic alicyclic musk, by activated sludge inocula was investigated using both the manometric respirometry test OECD 301F and the CO₂ evolution test. In addition to measuring its biodegradability, key steps of the upper part of the metabolic pathway responsible for Romandolide degradation were identified using extracts at different time points of incubation. Early metabolism of Romandolide yielded ester hydrolysis products, including Cyclademol (1-(3,3-dimethylcyclohexyl)ethanol). The principal metabolites after 31 days were identified as 3,3-dimethyl cyclohexanone and 3,3-dimethyl cyclohexyl acetate. Formation of 3,3-dimethyl cyclohexanone from Cyclademol by sludge was confirmed in subsequent experiments using Cyclademol as a substrate, indicating the involvement of an oxygen insertion reminiscent of a Baeyer-Villiger oxidation. Further mineralization of 3,3-dimethyl cyclohexanone was also confirmed in subsequent studies. Three steps were thus required for complete biodegradation of the alicyclic musk: (1) successive ester hydrolyses leading to the formation of Cyclademol with concomitant degradation of the resulting acids, (2) conversion of Cyclademol into 3,3-dimethyl cyclohexanone, and (3) further mineralization via ring cleavage.
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Affiliation(s)
- M Seyfried
- Firmenich SA, Route des Jeunes 1, 1211, Geneva, Switzerland,
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14
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Bosserman MA, Downey T, Noinaj N, Buchanan SK, Rohr J. Molecular insight into substrate recognition and catalysis of Baeyer-Villiger monooxygenase MtmOIV, the key frame-modifying enzyme in the biosynthesis of anticancer agent mithramycin. ACS Chem Biol 2013; 8:2466-77. [PMID: 23992662 DOI: 10.1021/cb400399b] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Baeyer-Villiger monooxygenases (BVMOs) have been shown to play key roles for the biosynthesis of important natural products. MtmOIV, a homodimeric FAD- and NADPH-dependent BVMO, catalyzes the key frame-modifying steps of the mithramycin biosynthetic pathway, including an oxidative C-C bond cleavage, by converting its natural substrate premithramycin B into mithramycin DK, the immediate precursor of mithramycin. The drastically improved protein structure of MtmOIV along with the high-resolution structure of MtmOIV in complex with its natural substrate premithramycin B are reported here, revealing previously undetected key residues that are important for substrate recognition and catalysis. Kinetic analyses of selected mutants allowed us to probe the substrate binding pocket of MtmOIV and also to discover the putative NADPH binding site. This is the first substrate-bound structure of MtmOIV providing new insights into substrate recognition and catalysis, which paves the way for the future design of a tailored enzyme for the chemo-enzymatic preparation of novel mithramycin analogues.
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Affiliation(s)
- Mary A. Bosserman
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Theresa Downey
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States
| | - Nicholas Noinaj
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Susan K. Buchanan
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States
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15
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Isolation and Characterization of a Marine Cyclohexylacetate-Degrading Bacterium Lutimaribacter litoralis sp. nov., and Reclassification of Oceanicola pacificus as Lutimaribacter pacificus comb. nov. Curr Microbiol 2013; 66:588-93. [DOI: 10.1007/s00284-013-0321-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 01/11/2013] [Indexed: 10/27/2022]
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16
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Yi T, Lee EH, Ahn YG, Hwang GS, Cho KS. Novel biodegradation pathways of cyclohexane by Rhodococcus sp. EC1. JOURNAL OF HAZARDOUS MATERIALS 2011; 191:393-396. [PMID: 21571424 DOI: 10.1016/j.jhazmat.2011.04.080] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 04/18/2011] [Indexed: 05/30/2023]
Abstract
The metabolism of cyclohexanes by Rodococcus sp. EC1 was investigated using a sequential tracking method of degradation intermediate. Evidence for the formation of cyclohexanol, cyclohexaone, 2-cyclohexen-1-one, and phenol was presented. EC1 metabolized cyclohexane to phenol by aromatization of 2-cyclohexen-1-one, and furthermore gamma-butyrolactone as an intermediate of 2-cyclohexen-1-one was formed. Aromatization by EC1 was confirmed using tetrahydrofuran. Tetrahydrofuran was metabolized through aromatization reaction, involving furan and 2,3-dihydrofuran as key intermediates. EC1 can degrade cyclohexane and tetrahydrofuran in aromatization via desaturation.
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Affiliation(s)
- Taewoo Yi
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul, Republic of Korea
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17
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Beam MP, Bosserman MA, Noinaj N, Wehenkel M, Rohr J. Crystal structure of Baeyer-Villiger monooxygenase MtmOIV, the key enzyme of the mithramycin biosynthetic pathway . Biochemistry 2009; 48:4476-87. [PMID: 19364090 PMCID: PMC2713373 DOI: 10.1021/bi8023509] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Baeyer-Villiger monooxygenases (BVMOs), mostly flavoproteins, were shown to be powerful biocatalysts for synthetic organic chemistry applications and were also suggested to play key roles for the biosyntheses of various natural products. Here we present the three-dimensional structure of MtmOIV, a 56 kDa homodimeric FAD- and NADPH-dependent monooxygenase, which catalyzes the key frame-modifying step of the mithramycin biosynthetic pathway and currently the only BVMO proven to react with its natural substrate via a Baeyer-Villiger reaction. MtmOIV's structure was determined by X-ray crystallography using molecular replacement to a resolution of 2.9 A. MtmOIV cleaves a C-C bond, essential for the conversion of the biologically inactive precursor, premithramycin B, into the active drug mithramycin. The MtmOIV structure combined with substrate docking calculations and site-directed mutagenesis experiments identifies several residues that participate in cofactor and substrate binding. Future experimentation aimed at broadening the substrate specificity of the enzyme could facilitate the generation of chemically diverse mithramycin analogues through combinatorial biosynthesis.
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Affiliation(s)
- Miranda P. Beam
- Department of Pharmaceutical Sciences, College of Pharmacy, and the Kentucky Center for Structural Biology, University of Kentucky, Lexington, KY 40536
| | - Mary A. Bosserman
- Department of Pharmaceutical Sciences, College of Pharmacy, and the Kentucky Center for Structural Biology, University of Kentucky, Lexington, KY 40536
| | - Nicholas Noinaj
- Department of Molecular and Cellular Biochemistry and Kentucky Center of Structural Biology, University of Kentucky, Lexington, KY 40536
| | - Marie Wehenkel
- Department of Pharmaceutical Sciences, College of Pharmacy, and the Kentucky Center for Structural Biology, University of Kentucky, Lexington, KY 40536
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences, College of Pharmacy, and the Kentucky Center for Structural Biology, University of Kentucky, Lexington, KY 40536
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18
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Iwaki H, Nakai E, Nakamura S, Hasegawa Y. Isolation and Characterization of New Cyclohexylacetic Acid-Degrading Bacteria. Curr Microbiol 2008; 57:107-10. [DOI: 10.1007/s00284-008-9158-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 02/26/2008] [Indexed: 10/22/2022]
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19
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Lee EH, Cho KS. Characterization of cyclohexane and hexane degradation by Rhodococcus sp. EC1. CHEMOSPHERE 2008; 71:1738-1744. [PMID: 18289631 DOI: 10.1016/j.chemosphere.2007.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2007] [Revised: 12/14/2007] [Accepted: 12/20/2007] [Indexed: 05/25/2023]
Abstract
Cyclohexane is a recalcitrant compound that is more difficult to degrade than even n-alkanes or monoaromatic hydrocarbons. In this study, a cyclohexane-degrading consortium was obtained from oil-contaminated soil by an enrichment culture method. Based on a 16S rDNA polymerase chain reaction-denaturing gradient gel electrophoresis method, this consortium was identified as comprising Alpha-proteobacteria, Actinobacteria, and Gamma-proteobacteria. One of these organisms, Rhodococcus sp. EC1, was isolated and shown to have excellent cyclohexane-degrading ability. The maximum specific cyclohexane degradation rate (Vmax) for EC1 was 246 micromol g-DCW(-1) (dry cell weight)h(-1). The optimum conditions of cyclohexane degradation were 25-35 degrees C and pH 6-8. In addition to its cyclohexane degradation abilities, EC1 was also able to strongly degrade hexane, with a maximum specific hexane degradation rate of 361 micromol g-DCW(-1)h(-1). Experiments using 14C-hexane revealed that EC1 mineralized 40% of hexane into CO2 and converted 53% into biomass. Moreover, EC1 could use other hydrocarbons, including methanol, ethanol, acetone, methyl tert-butyl ether, pyrene, diesel, lubricant oil, benzene, toluene, ethylbenzene, m-xylene, p-xylene and o-xylene. These findings collectively suggest that EC1 may be a useful biological resource for removal of cyclohexane, hexane, and other recalcitrant hydrocarbons.
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Affiliation(s)
- Eun-Hee Lee
- Department of Environmental Science and Engineering, Ewha Womans University, 11-1, Daehyun-dong, Seodaemun-Gu, Seoul 120-750, Republic of Korea
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20
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Iwaki H, Wang S, Grosse S, Bergeron H, Nagahashi A, Lertvorachon J, Yang J, Konishi Y, Hasegawa Y, Lau PCK. Pseudomonad cyclopentadecanone monooxygenase displaying an uncommon spectrum of Baeyer-Villiger oxidations of cyclic ketones. Appl Environ Microbiol 2006; 72:2707-20. [PMID: 16597975 PMCID: PMC1449013 DOI: 10.1128/aem.72.4.2707-2720.2006] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Baeyer-Villiger monooxygenases (BVMOs) are biocatalysts that offer the prospect of high chemo-, regio-, and enantioselectivity in the organic synthesis of lactones or esters from a variety of ketones. In this study, we have cloned, sequenced, and overexpressed in Escherichia coli a new BVMO, cyclopentadecanone monooxygenase (CpdB or CPDMO), originally derived from Pseudomonas sp. strain HI-70. The 601-residue primary structure of CpdB revealed only 29% to 50% sequence identity to those of known BVMOs. A new sequence motif, characterized by a cluster of charged residues, was identified in a subset of BVMO sequences that contain an N-terminal extension of approximately 60 to 147 amino acids. The 64-kDa CPDMO enzyme was purified to apparent homogeneity, providing a specific activity of 3.94 micromol/min/mg protein and a 20% yield. CPDMO is monomeric and NADPH dependent and contains approximately 1 mol flavin adenine dinucleotide per mole of protein. A deletion mutant suggested the importance of the N-terminal 54 amino acids to CPDMO activity. In addition, a Ser261Ala substitution in a Rossmann fold motif resulted in an improved stability and increased affinity of the enzyme towards NADPH compared to the wild-type enzyme (K(m) = 8 microM versus K(m) = 24 microM). Substrate profiling indicated that CPDMO is unusual among known BVMOs in being able to accommodate and oxidize both large and small ring substrates that include C(11) to C(15) ketones, methyl-substituted C(5) and C(6) ketones, and bicyclic ketones, such as decalone and beta-tetralone. CPDMO has the highest affinity (K(m) = 5.8 microM) and the highest catalytic efficiency (k(cat)/K(m) ratio of 7.2 x 10(5) M(-1) s(-1)) toward cyclopentadecanone, hence the Cpd designation. A number of whole-cell biotransformations were carried out, and as a result, CPDMO was found to have an excellent enantioselectivity (E > 200) as well as 99% S-selectivity toward 2-methylcyclohexanone for the production of 7-methyl-2-oxepanone, a potentially valuable chiral building block. Although showing a modest selectivity (E = 5.8), macrolactone formation of 15-hexadecanolide from the kinetic resolution of 2-methylcyclopentadecanone using CPDMO was also demonstrated.
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Affiliation(s)
- Hiroaki Iwaki
- National Research Council Canada, Biotechnology Research Institute, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
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