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The rising production and consumption of plastics, coupled with their intrinsic robustness, has resulted in the accumulation of up to 200 million tons of plastic waste in landfills and the environment each year. Of all these synthetic polymers, polyethylene terephthalate (PET) is the most widely used in the world. As environmental microorganisms have begun evolving their own biological means to metabolize plastics, they potentially present a sustainable method to recycle PET and retain its material value for subsequent use through biodegradation. Here, we evaluate the feasibility of using multiple PET-degrading bacterial strains (Thermobifida fusca, Ideonella sakaiensis, Pseudomonas mendocina) concurrently to develop an industrial co-culture solution. The growth behavior of each strain was evaluated at temperatures ranging from 30-60 °C and in a Hipolypepton-based media. UV-treated PET pellets were then incubated in monoculture and co-culture cell suspensions for 2 days, and degradation was measured through a spectrophotometric assay. A 1:1 T. fusca/I. sakaiensis co-culture was found to achieve a higher biodegradation efficiency compared to I. sakaiensis monoculture but not compared to T. fusca monoculture, suggesting the need for further optimization of degradation conditions. Although our studies demonstrate the great potential of biodegradation as a solution for the plastic waste crisis, the direct application of microbes may not be suitable for industrial use when compared to alternative biodegradative methods. [ABSTRACT FROM AUTHOR]

The process of bioethanol production from biomass comprises pretreatments and enzyme-mediated hydrolysis to convert lignocellulose into fermentable sugars. Because of the recalcitrant character of cellulose, the enzymatic hydrolysis is considered the major challenge in this process to be economically competitive. These technical difficulties highlight the need for the discovery of new enzymes to optimize and lower the cost of current technologies. Microorganisms have developed efficient systems for cellulose degradation. Among cellulolytic microbes, Thermobifida fusca possesses great physiological and cellulolytic characteristics (thermostability, high activity and tolerance to a broad pH range) making it an interesting organism to be studied from an applied perspective. In this review we describe the main enzymes/proteins produced by T.fusca (cellulases, xylanases, mannanase, manosidase, CBM33 and CelR), the effect of substrate on T. fusca proteome, enzyme improvement approaches, synergism between enzymes/proteins and artificial cellulosomes. [ABSTRACT FROM AUTHOR]

In this paper, two types of bacterial fusion protein, cutinase-CBMCel6A and cutinase-CBMCenA, were used to modify the surface of cellulose acetate fibre. The enzyme binding on cellulose acetate fibres and the hydrolysis of acetyl groups were monitored. Water absorbency and dye uptake were measured to assess the extent of enzymatic modification. The results demonstrated that cutinase-carbohydrate-binding module (CBM) has a greater effect on cellulose acetate fibres than that of cutinase. The use of non-ionic surfactant Triton X-100 could further improve enzymatic modification of cellulose acetate fibres in terms of wettability and dyeability. Scanning electron microscopy confirmed that both cutinase-CBMs could lead to the formation of carving characters on the surface of treated cellulose acetate fibres. Our studies provide a foundation for the potential application of cutinase-CBM in the surface modification of cellulose acetate fibre. [ABSTRACT FROM AUTHOR]

Knitted fabrics made from poly(ethylene terephthalate) fibres were treated with an enzyme preparation from Thermobifida fusca KW3b showing hydrolytic activity on p-nitrophenyl butyrate. The fabrics were also treated with NaOH and the results were compared. Both enzyme- and alkaline-treated fabrics showed an increase in reactive dye uptake, vertical wicking height and water absorption capacity of the fabrics indicating an increased surface hydrophilicity. However, X-ray photoelectron (XPS) and energy-dispersive spectroscopy (EDS) did not give conclusive results on the presence of newly introduced hydrophilic groups on the surface of the fibres. Analysis of the enzyme-treated poly(ethylene terephthalate) fibres by scanning electron microscopy (SEM) and by atomic force microscopy (AFM) indicated an increase in surface roughness of the fibres, which may contribute to the observed increased hydrophilicity of the PET fabrics. However, much longer treatment times (24 h) were required to obtain these effects with the enzymes compared to the chemical treatment (1 h). [ABSTRACT FROM AUTHOR]