RESUMEN
Accumulation of electronic waste has increased catastrophically and out of that various plastic resins constitute one of the leading thrown out materials in the electronic machinery. Enrichment medium, containing high impact polystyrene (HIPS) with decabromodiphenyl oxide and antimony trioxide as sole carbon source, was used to isolate microbial cultures. The viability of these cultures in the e-plastic containing mineral medium was further confirmed by triphenyl tetrazolium chloride (TTC) reduction test. Four cultures were identified by 16S rRNA sequencing as Enterobacter sp., Citrobacter sedlakii, Alcaligenes sp. and Brevundimonas diminuta. Biodegradation experiments were carried out in flask level and gelatin supplementation (0.1% w/v) along with HIPS had increased the degradation rate to a maximum of 12.4% (w/w) within 30days. This is the first report for this kind of material. The comparison of FTIR, NMR, and TGA analysis of original and degraded e-plastic films revealed structural changes under microbial treatment. Polystyrene degradation intermediates in the culture supernatant were also detected using HPLC analysis. The gravity of biodegradation was validated by morphological changes under scanning electron microscope. All isolates displayed depolymerase activity to substantiate enzymatic degradation of e-plastic.
Asunto(s)
Antimonio/química , Biodegradación Ambiental , Residuos Electrónicos , Éteres Difenilos Halogenados/química , Plásticos , Poliestirenos/metabolismo , Bacterias/enzimología , Bacterias/metabolismo , Biopelículas , Biomasa , Interacciones Hidrofóbicas e Hidrofílicas , Oxidación-Reducción , Poliestirenos/química , ARN Ribosómico 16S/análisisRESUMEN
Bioplastics are eco-friendly and derived from renewable biomass sources. Innovation in recycling methods will tackle some of the critical issues facing the acceptance of bioplastics. Polylactic acid (PLA) is the commonly used and well-studied bioplastic that is presumed to be biodegradable. Considering their demand and use in near future, exploration for microbes capable of bioplastic degradation has high potential. Four PLA degrading strains were isolated and identified as Penicillium chrysogenum, Cladosporium sphaerospermum, Serratia marcescens and Rhodotorula mucilaginosa. A consortium of above strains degraded 44 % (w/w) PLA in 30 days time in laboratory conditions. Subsequently, the microbial consortium employed effectively for PLA composting.
RESUMEN
As a biodegradable polyester, polylactide (PLA) has applications as a packaging material, in biomedical fields and tissue engineering. With the dual aim of improving its properties and biodegradability, PLA was blended with other polymers such as gum arabic, thermoplastic starch, microcrystalline cellulose, polyethylene glycol and polyhydroxy butyrate in 1:1 (w/w) by melt-blending technique. The thermal properties of the blends were compared with that of unblended PLA by thermo-gravimetric analysis. Biodegradation using Lentzea waywayandensis was in the order of PLA-gum arabic > PLA-thermoplastic starch > PLA(virgin) > PLA-microcrystalline cellulose > PLA-polyethylene glycol > PLA-polyhydroxy butyrate. Weight loss of 99 % (w/w) was noted within 4 days for PLA-thermoplastic starch and PLA-gum arabic blends.