ABSTRACT: Biofilm formation and degradation of commercially available biodegradable plastic films by bacterial consortium in the freshwater environments.
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.
2020-09-25 | PXD018391 | Pride
Project description:Soil microbial communities associated with biodegradable plastic mulch films
Project description:Biodegradable plastics are one possible solution for reducing plastic waste, yet the mechanisms and organisms involved in their degradation in the aquatic environment remain understudied. In this study, we have enriched a microbial community from North Sea water and sediment, capable of growing on the polyester poly(butylene succinate). This culture was grown on two other biodegradable polyesters, polycaprolactone and ecovio® FT (a PBAT-based blended biodegradable plastic), and the differences between community structure and activity on these three polymers were determined by metagenomics and metaproteomics. We have seen that the plastic supplied drives the community structure and activity. Setups growing on ecovio® FT were more diverse, yet showed the lowest degradation, while poly(butylene succinate) and polycaprolactone resulted in a less diverse community but much higher degradation efficiencies. The dominating species were Alcanivorax sp., Thalassobius sp., or Pseudomonas sp., depending on the polymer supplied. Furthermore, we have observed that Gammaproteobacteria were more abundant and active within the biofilm and Alphaproteobacteria within the free-living fraction of the enrichments. Two of the three PETase-like enzymes isolated were expressed as tandems (Ple -tan1 &Ple – tan2) and all three were produced by Pseudomonas sp. Of those, Ple-tan1 was most active on all three substrates and also the most thermostable. Overall, we could show that all three plastics investigated can be mineralized by bacteria naturally occurring within the marine environment and characterize some of the enzymes involved in the degradation process.
Project description:Biofilms are ubiquitous in natural, medical, and engineering environments. While most antibiotics that primarily aim to inhibit cell growth may result in bacterial drug resistance, biofilm inhibitors do not affect cell growth and there is less chance of developing resistance. This work sought to identify novel, non-toxic and potent biofilm inhibitors from Streptomyces bacteria for reducing the biofilm formation of Pseudomonas aeruginosa PAO1. Out of 4300 Streptomyces strains, one species produced and secreted peptide(s) to inhibit P. aeruginosa biofilm formation by 93% without affecting the growth of planktonic cells. Global transcriptome analyses (DNA microarray) revealed that the supernatant of the Streptomyces 230 strain induced phenazine, pyoverdine, and pyochelin synthesis genes. Electron microscopy showed that the supernatant of Streptomyces 230 strain reduced the production of polymeric matrix in P. aeruginosa biofilm cells, while the Streptomyces species enhanced swarming motility of P. aeruginosa. Therefore, current study suggests that Streptomyces bacteria are an important resource of biofilm inhibitors as well as antibiotics. For the microarray experiments, P. aeruginosa were inoculated in 25 0ml of LB medium in 1000 ml shake flasks with overnight cultures that were diluted 1:100. Streptomyces 230 strain culture media was added in at 1% . Cells were cultured with 10g of glass wool in LB at 37M-BM-0C with 100 rpm shaking for 7 hrs. Cells were immediately chilled with dry ice and 95% ethanol (to prevent RNA degradation) for 30 sec before centrifugation in 50 ml centrifuge tubes at 13,000 g for 2 min; cell pellets were frozen immediately with dry ice and stored -80M-BM-0C. RNA was isolated using Qiagen RNeasy mini Kit (Valencia, CA, USA). RNA quality was assessed by Agilent 2100 bioanalyser using the RNA 6000 Nano Chip (Agilent Technologies, Amstelveen, The Netherlands), and quantity was determined by ND-1000 Spectrophotometer (NanoDrop Technologies, Inc., DE, USA).
Project description:Biofilms are structured communities of tightly associated cells that constitute the predominant state of bacterial growth in natural and human-made environments. Although the core genetic circuitry that controls biofilm formation in model bacteria such as Bacillus subtilis has been well characterized, little is known about the role that metabolism plays in this complex developmental process. Here, we performed a time-resolved analysis of the metabolic changes associated with pellicle biofilm formation and development in B. subtilis by combining metabolomic, transcriptomic, and proteomic analyses. We report a surprisingly widespread and dynamic remodeling of metabolism affecting central carbon metabolism, primary biosynthetic pathways, fermentation pathways, and secondary metabolism. Most of these metabolic alterations were hitherto unrecognized as biofilm-associated. For example, we observed increased activity of the tricarboxylic acid (TCA) cycle during early biofilm growth, a shift from fatty acid biosynthesis to fatty acid degradation, reorganization of iron metabolism and transport, and a switch from acetate to acetoin fermentation. Close agreement between metabolomic, transcriptomic, and proteomic measurements indicated that remodeling of metabolism during biofilm development was largely controlled at the transcriptional level. Our results also provide insights into the transcription factors and regulatory networks involved in this complex metabolic remodeling. Following these results, we demonstrate that acetoin production via acetolactate synthase is essential for robust biofilm growth and has the dual role of conserving redox balance and maintaining extracellular pH. This study represents a comprehensive systems-level investigation of the metabolic remodeling occurring during B. subtilis biofilm development that will serve as a useful roadmap for future studies on biofilm physiology.
Project description:Neisseria gonorrhoeae, the etiologic agent of gonorrhea, is frequently asymptomatic in women, often leading to chronic infections. One factor contributing to this may be biofilm formation. N. gonorrhoeae can form biofilms over glass and plastic surfaces. There is also evidence that biofilm formation may occur during natural cervical infection. To further study the mechanism of this biofilm formation, transcriptional profiles of N. gonorrhoeae biofilm were compared to planktonic profiles. Biofilm RNA was extracted from N. gonorrhoeae 1291 grown for 48 hours in continuous flow chambers over glass. Planktonic RNA was extracted from the biofilm runoff. When biofilm was compared to planktonic growth, 3.8 % of the genome was differentially regulated. Genes highly up-regulated in biofilm included aniA, norB, and ccp, which play critical roles in anaerobic metabolism and oxidative stress tolerance. Down-regulated genes included the nuo gene cluster (NADH dehydrogenase) and the cytochrome bcI complex, which are involved in aerobic respiration and are thought to contribute to endogenous oxidative stress. Furthermore, we determined that aniA, ccp, and norB insertional mutants are attenuated for biofilm formation over glass and transformed human cervical epithelial cells (THCEC). This data suggests that biofilm formation could minimize oxidative stress during cervical infection and allow N. gonorrhoeae to maintain a nitric oxide steady state that may be anti-inflammatory.
Project description:Biofilms are ubiquitous in natural, medical, and engineering environments. While most antibiotics that primarily aim to inhibit cell growth may result in bacterial drug resistance, biofilm inhibitors do not affect cell growth and there is less chance of developing resistance. This work sought to identify novel, non-toxic and potent biofilm inhibitors from Streptomyces bacteria for reducing the biofilm formation of Pseudomonas aeruginosa PAO1. Out of 4300 Streptomyces strains, one species produced and secreted peptide(s) to inhibit P. aeruginosa biofilm formation by 93% without affecting the growth of planktonic cells. Global transcriptome analyses (DNA microarray) revealed that the supernatant of the Streptomyces 230 strain induced phenazine, pyoverdine, and pyochelin synthesis genes. Electron microscopy showed that the supernatant of Streptomyces 230 strain reduced the production of polymeric matrix in P. aeruginosa biofilm cells, while the Streptomyces species enhanced swarming motility of P. aeruginosa. Therefore, current study suggests that Streptomyces bacteria are an important resource of biofilm inhibitors as well as antibiotics.