Biodegradation of PHB by Soil Microorganisms

Polymers exposed to the environment are degraded by their hydrolysis, mechanical, thermal, oxidative, and photochemical destruction, and biodegradation [7, 38, 55, 56]. One of the valuable properties of PHB is its biodegradability, which can be evaluated using various field and laboratory tests. Requirements for the biodegradability of PHB may vary in accordance with its applications. The most attractive property of PHB with 

FIGURE 1.3 Molded PHB objects for various applications. In soil burial or composting experiments, such objects biodegrade in about 3 months [4], 

Biodegradability of PHB films under aerobic, microaerobic, and anaerobic conditions in the presence and absence of nitrate by microbial populations of soil, sludge from anaerobic and nitrifying/denitrifying reactors. 

FIGURE 1.4 Undegraded PHB film (A) and PHB films with different degrees of degradation after 2 months incubation in soil suspension anaerobic conditions without nitrate (B), microaerobic conditions without nitrate (C), and microaerobic conditions with 

PHB biodegradation in the enriched culture obtained from soil on the medium used to cultivate denitrifying bacteria (Gil tai medium) has also been studied. The dominant bacterial species. Pseudomonas fluorescens and Pseudomonas stutzeri, have been identified in this enrichment culture. Under denitrifying conditions, PHB films were completely degraded for 7 days. Both the film weight and of PHB decreased with time. In 

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