Project description:Although the biodegradation of biodegradable plastics in soil and compost is well-studied, there is little knowledge on the metabolic mechanisms of synthetic polymers degradation by marine microorganisms. Here, we present a multiomics study to elucidate the biodegradation mechanism of a commercial aromatic-aliphatic copolyester film by a marine microbial enrichment culture. The plastic film and each monomer can be used as sole carbon source. Our analysis showed that the consortium synergistically degrades the polymer, different degradation steps being performed by different members of the community. Analysis of gene expression and translation profiles revealed that the relevant degradation processes in the marine consortium are closely related to poly(ethylene terephthalate) biodegradation from terrestrial microbes. Although there are multiple genes and organisms with the potential to perform a degradation step, only a few of these are active during biodegradation. Our results elucidate the potential of marine microorganisms to mineralize biodegradable plastic polymers and describe the mechanisms of labor division within the community to get maximum energetic yield from a complex synthetic substrate.
Project description:The use of carbon labelled PBAT units allowed us to follow biodegradation of all PBAT building blocks. The presented workflow is a novel approach to study the fundamental steps in polymer biodegradation in complex systems.
Project description:We have developed a 60-mer oligonucleotide multibacterial microarray for detection and expression profiling of biodegradative genes and bacterial diversity (16S rRNA gene) in different habitats contaminated with varieties of hazardous chemicals. The genes selected were involved in biodegradation and biotransformation of various groups of compounds viz. nitroaromatic compounds (148 genes), chloroaromatic compounds (75 genes), monoaromatic compounds (373 genes), polyaromatic hydrocarbons (174 genes), pesticides/ herbicides (34 genes), alkanes/aliphatics (185 genes) and heavy metals (68 genes), which covered a total number of 133 chemicals. The efficiency (specificity, detection sensitivity) of the developed array was evaluated using the labeled genomic DNA of pure bacterial strains, Escherichia coli DH5α and Sphingomonas sp. strain NM-05 (involved in the biodegradation of γ-hexachlorohexane isolated from IPL, Lucknow) at different concentrations of 300ng, 500ng, 800ng, 1000ng and 1250ng. The specificity of the developed array was further validated using mixed cultures containing three strains (Sphingomonas sp. strain NM-05, Rhodococcus sp. strain RHA1 and Bordetella sp. strain IITR-02) involved in biodegradation of γ-hexachlorohexane, biphenyl and chlorobenzenes respectively. The mixed culture also contained non-target/non-degrader strains (E. coli DHα, E.coli BL21 and E.coli K12 NCTC50192). The developed array was applied for profiling using the total soil DNA in five contaminated habitats of north India, viz. chloroaromatic chemicals contaminated site (India Pesticide Limited, Chinhat, Lucknow), a river sediments (Gomti river sediment, Lucknow), heavy metal industry dump site (Jajmau industrial area Kanpur), a effluent treatment plant (CETP along Ganges river near Kanpur), and an oil refinery (Mathura oil refinery). Hybridization of 16S rRNA probes revealed the presence of bacteria similar to well characterized genera involved in biodegradation of pollutants. Genes involved in complete degradation pathways for hexachlorocyclohexane (lin), 1,2,4-trichlorobenzene (tcb), naphthalene (nah), phenol (mph), biphenyl (bph), benzene (ben), toluene (tbm), xylene (xyl), phthalate (pht), Salicylate (sal) and resistance to mercury (mer) were detected with highest intensity. The most abundant genes belonged to hydroxylases, monooxygenases and dehydrogenases which were present in all the five samples. Many compound specific genes which initiate the degradation pathway were also detected. Thus, the array developed and validated here may be useful in assessing the biodegradative potential and composition of environmentally useful bacteria in hazardous ecosystems.
Project description:We isolated a strain that efficiently degrades tetracycline and compared its proteomic data in the presence and absence of tetracycline to analyze the molecular mechanism of tetracycline biodegradation