Omega-oxygenation of the alkyl sidechain of linear alkylbenzenesulfonate (LAS) surfactant in Parvibaculum lavamentivorans(T)

Multispecies Diesel Fuel Biodegradation and Niche Formation Are Ignited by Pioneer Hydrocarbon-Utilizing Proteobacteria in a Soil Bacterial Consortium

A soil bacterial consortium that was grown on diesel fuel and consisted of more than 10 members from different genera was maintained through repetitive subculturing and was utilized as a practical model to investigate a bacterial community that was continuously exposed to petroleum hydrocarbons. Through metagenomics analyses, consortium member isolation, growth assays, and metabolite identification which supported the linkage of genomic data and functionality, two pioneering genera, Sphingobium and Pseudomonas, whose catabolic capabilities were differentiated, were found to be responsible for the creation of specialized ecological niches that were apparently occupied by other bacterial members for survival within the consortium. Coexisting genera Achromobacter and Cupriavidus maintained their existence in the consortium through metabolic dependencies by utilizing hydrocarbon biotransformation products of pioneer metabolism, which was confirmed through growth tests and identification of biotransformation products of the isolated strains. Pioneering Sphingobium and Pseudomonas spp. utilized relatively water-insoluble hydrocarbon parent compounds and facilitated the development of a consortium community structure that resulted in the creation of niches in response to diesel fuel exposure which were created through the production of more-water-soluble biotransformation products available to cocolonizers. That these and other organisms were still present in the consortium after multiple transfers spanning 15 years provided evidence for these ecological niches. Member survival through occupation of these niches led to robustness of each group within the multispecies bacterial community. Overall, these results contribute to our understanding of the complex ecological relationships that may evolve during prokaryotic hydrocarbon pollutant biodegradation.IMPORTANCE There are few metagenome studies that have explored soil consortia maintained on a complex hydrocarbon substrate after the community interrelationships were formed. A soil bacterial consortium maintained on diesel fuel was utilized as a practical model to investigate bacterial community relationships through metagenomics analyses, consortium member isolation, growth assays, and metabolite identification, which supported the linkage of genomic data and functionality. Two pioneering genera were responsible for the biodegradation of aromatics and alkanes by initiating biotransformation and thereby created specialized niches that were populated by other members. A model that represents these relationships was constructed, which contributes to our understanding of the complex ecological relationships that evolve during prokaryotic hydrocarbon pollutant biodegradation.

Detergent-like stressor and nutrient in metabolism of Penicillium chrysogenum

The influence of detergents on the metabolism of Penicillium chrysogenum from two aspects, as a stress factor and potential nutrient, was studied. The fungus was isolated from the river bed Lepenica, Kragujevac, at a place where sewage domestic wastewater discharged into the river. The fungus was grown in a liquid nutrient medium according to Czapek with and without addition of commercial detergent (MERIX, Henkel, Serbia) at a concentration of 0.3% and 0.5%. The biochemical changes of pH, redox potential, free and total organic acids, total dry weight biomass, activity of alkaline and acid invertase and alkaline phosphatase were evaluated from day 3 to day 16 of the fungus growth. At the same time, detergent disappearance in terms of methylene blue active substances in the medium was measured. The detergent at a concentration of 0.5% showed a fungicide effect. In the medium with 0.3% of detergent, there was increased pH and concentration of organic acids, but decreased redox potential and total dry weight biomass. The detergent also showed an inhibitory effect on invertase and phosphatase activity. P. chrysogenum decomposed 50.2% of the total detergent concentration for an experimental period of 16 days.

Two enzymes of a complete degradation pathway for linear alkylbenzenesulfonate (LAS) surfactants: 4-sulfoacetophenone Baeyer-Villiger monooxygenase and 4-sulfophenylacetate esterase in Comamonas testosteroni KF-1

Complete biodegradation of the surfactant linear alkylbenzenesulfonate (LAS) is accomplished by complex bacterial communities in two steps. First, all LAS congeners are degraded into about 50 sulfophenylcarboxylates (SPC), one of which is 3-(4-sulfophenyl)butyrate (3-C(4)-SPC). Second, these SPCs are mineralized. 3-C(4)-SPC is mineralized by Comamonas testosteroni KF-1 in a process involving 4-sulfoacetophenone (SAP) as a metabolite and an unknown inducible Baeyer-Villiger monooxygenase (BVMO) to yield 4-sulfophenyl acetate (SPAc) from SAP (SAPMO enzyme); hydrolysis of SPAc to 4-sulfophenol and acetate is catalyzed by an unknown inducible esterase (SPAc esterase). Transcriptional analysis showed that one of four candidate genes for BVMOs in the genome of strain KF-1, as well as an SPAc esterase candidate gene directly upstream, was inducibly transcribed during growth with 3-C(4)-SPC. The same genes were identified by enzyme purification and peptide fingerprinting-mass spectrometry when SAPMO was enriched and SPAc esterase purified to homogeneity by protein chromatography. Heterologously overproduced pure SAPMO converted SAP to SPAc and was active with phenylacetone and 4-hydroxyacetophenone but not with cyclohexanone and progesterone. SAPMO showed the highest sequence homology to the archetypal phenylacetone BVMO (57%), followed by steroid BVMO (55%) and 4-hydroxyacetophenone BVMO (30%). Finally, the two pure enzymes added sequentially, SAPMO with NADPH and SAP, and then SPAc esterase, catalyzed the conversion of SAP via SPAc to 4-sulfophenol and acetate in a 1:1:1:1 molar ratio. Hence, the first two enzymes of a complete LAS degradation pathway were identified, giving evidence for the recruitment of members of the very versatile type I BVMO and carboxylester hydrolase enzyme families for the utilization of a xenobiotic compound by bacteria.

Complete genome sequence of Parvibaculum lavamentivorans type strain (DS-1(T))

Parvibaculum lavamentivorans DS-1(T) is the type species of the novel genus Parvibaculum in the novel family Rhodobiaceae (formerly Phyllobacteriaceae) of the order Rhizobiales of Alphaproteobacteria. Strain DS-1(T) is a non-pigmented, aerobic, heterotrophic bacterium and represents the first tier member of environmentally important bacterial communities that catalyze the complete degradation of synthetic laundry surfactants. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,914,745 bp long genome with its predicted 3,654 protein coding genes is the first completed genome sequence of the genus Parvibaculum, and the first genome sequence of a representative of the family Rhodobiaceae.

Bacterial communities from shoreline environments (costa da morte, northwestern Spain) affected by the prestige oil spill

The bacterial communities in two different shoreline matrices, rocks and sand, from the Costa da Morte, northwestern Spain, were investigated 12 months after being affected by the Prestige oil spill. Culture-based and culture-independent approaches were used to compare the bacterial diversity present in these environments with that at a nonoiled site. A long-term effect of fuel on the microbial communities in the oiled sand and rock was suggested by the higher proportion of alkane and polyaromatic hydrocarbon (PAH) degraders and the differences in denaturing gradient gel electrophoresis patterns compared with those of the reference site. Members of the classes Alphaproteobacteria and Actinobacteria were the prevailing groups of bacteria detected in both matrices, although the sand bacterial community exhibited higher species richness than the rock bacterial community did. Culture-dependent and -independent approaches suggested that the genus Rhodococcus could play a key role in the in situ degradation of the alkane fraction of the Prestige fuel together with other members of the suborder Corynebacterineae. Moreover, other members of this suborder, such as Mycobacterium spp., together with Sphingomonadaceae bacteria (mainly Lutibacterium anuloederans), were related as well to the degradation of the aromatic fraction of the Prestige fuel. The multiapproach methodology applied in the present study allowed us to assess the complexity of autochthonous microbial communities related to the degradation of heavy fuel from the Prestige and to isolate some of their components for a further physiological study. Since several Corynebacterineae members related to the degradation of alkanes and PAHs were frequently detected in this and other supralittoral environments affected by the Prestige oil spill along the northwestern Spanish coast, the addition of mycolic acids to bioremediation amendments is proposed to favor the presence of these degraders in long-term fuel pollution-affected areas with similar characteristics.

Parvibaculum lavamentivorans DS-1T degrades centrally substituted congeners of commercial linear alkylbenzenesulfonate to sulfophenyl carboxylates and sulfophenyl dicarboxylates

Commercial linear alkylbenzenesulfonate (LAS) contains 20 congeners of linear alkanes (C(10) to C(13)) substituted subterminally with the 4-sulfophenyl moiety in any position from lateral to central. Parvibaculum lavamentivorans DS-1(T) degrades each of eight laterally substituted congeners [e.g., 2-(4-sulfophenyl)decane (2-C10-LAS); herein, compounds are named systematically by chain length (e.g., C(10)) and by the position of the substituent on the chain (e.g., position 2)] to a major sulfophenyl carboxylate [SPC; here 3-(4-sulfophenyl)butyrate (3-C4-SPC)] and two minor products, namely, the alpha,beta-unsaturated SPC (SPC-2H, here 3-C4-SPC-2H) and the SPC+2C (here 5-C6-SPC) species (D. Schleheck, T. P. Knepper, K. Fischer, and A. M. Cook, Appl. Environ. Microbiol. 70:4053-4063). The degradation of centrally substituted congeners by strain DS-1 was examined in this work. 5-C10-LAS yielded not only the predicted 4-C8-SPC, 4-C8-SPC-2H, and 6-C10-SPC (about 70% of products) but also sulfophenyl dicarboxylates (SPdC), i.e., C6-, C8-, and C10-SPdC. These were identified by electrospray ionization-mass spectrometry (ESI-MS) after separation by high-pressure liquid chromatography (HPLC). ESI ion-trap MS and ESI-time of flight-MS were used to confirm the identities of key intermediates. Different mixtures of congeners obtained by separation of commercial LAS by HPLC were degraded, and the degradative products were compared. If a congener carried the sulfophenyl substituent on the 5, 6, or 7 position, SPdCs were formed as well as SPC, SPC-2H, and SPC+2C, whereas the substituent on the 2, 3, or 4 position yielded only SPC, SPC-2H, and SPC+2C. Some 50 products were generated from the 20 LAS congeners: 11 major SPCs, each with an SPC-2H and an SPC+2C (i.e., 33 SPC and SPC-2H species), and about 17 SPdC species. A large array of compounds, many in low quantities, is thus generated by P. lavamentivorans DS-1 during the degradation of commercial LAS.