Biodegradable enzymes

Rivard, C., Moens, L., Roberts, K., Brigham, J., and Kelley, S., 1995, Starch esters as biodegradable plastics - Effects of ester group chain leiigth and degree of substitution on anaerobic biodegradation. Enzym. Microb. Technol 17 848-852. 

Biodegradation - Enzymes present in the sample can hydrolyze conjugated material and release extra material for analysis or alter the analyte reducing the amount available for assay. Microbial contamination can have a similar effect and can metabolize components of the sample and produce others. This activity can affect dissolved oxygen and carbon dioxide through to nitrogenous compound and carbohydrates. 

Typical biodegradants enzymes, animal tissue active components, basic environment biodegradation is hindered by previous UV degradation Artsis, M 1 Bonartsev, A P lordan-skll, A L Bonartseva, G A Zaikov, G E, Mol. Cryst. Liq. Ciys, 523, 21-49, 2010 Sadi, R K Fechine, G J M Demarquette, N R, Polym. Deg. Stab., 95, 2318-27,2010. 

Recent patents and pubHcations describe process improvements. Conversions can be followed by on-line hplc (93). The enzyme amidase can be used to reduce residual monomers (94—96). A hydrogenation process for reduction of acrylamide in emulsions containing more that 5% residual monomer has been patented (95). Biodegradable oils have been developed (97). 

Although the antibacterial and antifungal activities of bialaphos and phosphinothricin were not found to be usehil, the two agents were later used as biodegradeable, relatively nonselective, postemergent herbicides. Glutamine synthetase inhibition is toxic to plants because the enzyme is key to ammonia assimilation. There is some selectivity for individual plant species as shown by the LD for bialaphos ranging from 0.125 to 8.5 kg/ha (301—303). 

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]. 

Some enzymes isolated in studies of primary alcohol sulfate biodegradation are specific for these sulfates [390,396]. However, other enzymes are more versatile. A strain isolated by Payne et al. [408] was capable of hydrolyzing secondary alcohol sulfates and also primary alcohol sulfates. Similar results were found by Vaicum and Eminovici [409]. 

They are resistant to chemical, photochemical, and enzyme-mediated biodegradations. 

Compared with tar, which has a relatively short lifetime in the marine environment, the residence times of plastic, glass and non-corrodible metallic debris are indefinite. Most plastic articles are fabricated from polyethylene, polystyrene or polyvinyl chloride. With molecular weights ranging to over 500,000, the only chemical reactivity of these polymers is derived from any residual unsaturation and, therefore, they are essentially inert chemically and photochemically. Further, since indigenous microflora lack the enzyme systems necessary to degrade most of these polymers, articles manufactured from them are highly resistant or virtually immune to biodegradation. That is, the properties that render plastics so durable... 

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