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Study of microbial communities involved in biodegradation of poly (e-caprolactone) / modified corn starch / soy protein isolate on different soils


The development of biodegradable polymers has been the subject of research in different areas with emphasis on environmental issues. Biodegradable plastics with high percent of raw material from renewable resources are substituting conventional plastics in many applications such as disposable packaging, horticultural pots and agricultural mulches, especially in developed countries. Poly (e-caprolactone) and starch blends are an example of these materials. Poly (e-caprolactone) blends present accelerated biodegradation; however, the environment where it is deposited is important in the process of biodegradation. To better understand the biodegradation process, which is a result from the enzymatic action of microorganisms on the decomposing material, it is necessary to understand the interactions between organisms and biodegradable plastics. Previous work developed by the research group of Dr. Cardoso Elke (ESALQ / USP) and Dr. Lucia Mei (Unicamp) showed that there is great difference in the mineralization of the mixture of poly (e-caprolactone) / modified corn starch / soy protein isolated in different soil textures. In this context, this project aims to continue the study of biodegradation of the blends in order to understand the possible interactions between soil texture, mineralization and microbial diversity. We intend to investigate the changes in microbial diversity of soils as a function of biodegradation of the blends based on poly (e-caprolactone) / modified corn starch / soy protein isolate and N-fertilizer addition. Samples of the blend will be subjected to a biodegradation test in two soils of different textures, with and without ammonium phosphate addition. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method with subsequent DNA sequencing will be used to assess changes in soil microbial community. (AU)