Bacterial Biodegradation

Audrey, W., Rahul, B., Amar, K.M. Novel talc-filled biodegradable bacterial polyester composites. Ind. Eng. Chem. Res. 45, 7497-7503 (2006)... 

Glycol Ether Theoretical Oxygen Demand , mg 02/mg Biodegradation % Bacterial IC50 mg/L Fathead Minnow 4 l LC50 mg/L Daphnia Magna LCso mg/L... 

Figure 9.10 Poly-p-hydroxybutyrate (PHB), the biodegradable bacterial polyester, n =...

Barrier Properties of Biodegradable Bacterial Polyester Films... 

Typical biodegradants bacterial hydrolases filametous fungus Phanerochaete Chrysosporium) Klun, U Ffriedrich, J Kizan, A, Polym. Deg. Stab., 79, 99-104, 2003. 

PHAs are biodegradable bacterial polyesters used as a substitute for nonbiodegradable petroleum polyester products. Polyhydroxybutyrate (PHB) is the most studied example of... 

Certain bacterial species produce polymers of y-hydroxybutyric acid and other hydroxyalkanoic acids as storage polymers. These are biodegradable polymers with some desirable properties for manufacture of biodegradable packaging materials, and considerable effort is being devoted by ICI Ltd. and others to the development of bacterial fermentation processes to produce these polymers at a high molecular weight (66). 

Other bacterial strains identified as biodegrading poly(vinyl alcohol) iaclude Flavobacterium (95) 2in.dFicinetobacter (96) and many others, as well as fungi, molds, and yeasts (97). Industrial evaluations at Du Pont (98) and Air Products (99) iadicate that over 90% of poly(vinyl alcohol) entering wastewater treatment plants is removed, and hence no environmental pollution is likely. 

Alcohol and alcohol ether sulfates are commonly considered as extremely rapid in primary biodegradation. The ester linkage in the molecule of these substances, prone to chemical hydrolysis in acid media, was considered the main reason for the rapid degradation. The hydrolysis of linear primary alcohol sulfates by bacterial enzymes is very easy and has been demonstrated in vitro. Since the direct consequence of this hydrolysis is the loss of surfactant properties, the primary biodegradation, determined by the methylene blue active substance analysis (MBAS), appears to be very rapid. However, the biodegradation of alcohol sulfates cannot be explained by this theory alone as it was proven by Hammerton in 1955 that other alcohol sulfates were highly resistant [386,387]. 

The first step in the complete biodegradation of primary alcohol sulfates seems to be the hydrolysis to yield alcohol. Sulfatases are able to hydrolyze primary alcohol sulfates. Different authors have isolated and used several sulfia-tase enzymes belonging to Pseudomonas species. The alcohol obtained as a result of the hydrolysis, provided that dehydrogenases have been removed to avoid the oxidation of the alcohol, was identified by chromatography and other methods [388-394]. The absence of oxygen uptake in the splitting of different primary alcohol sulfates also confirms the hydrolysis instead of oxidation [395, 396]. The hydrolysis may acidify the medium and stop the bacterial growth in the absence of pH control [397-399]. 

Poly(3-hydroxybutyrate) (1.8) is a bacterial polyester that behaves as an acceptable thermoplastic, yet can be produced from renewable agricultural feedstocks and is biodegradable. It is typically produced not in the pure state. 

Awasthi N, Manickam N, Kumar A. 1997. Biodegradation of endosulfan by a bacterial coculture. Bull Environ Contam Toxicol 59(6) 928-934. 

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