Avaliação da biodegradação do diesel e biodiesel por fungo Rhizopus ssp., Mucor ssp., Aspergillus ssp., Penicillium ssp e Fusarium ssp através de bioindicador vegetal [Vigna unguiculata (L.) Walp.]

Abstract

Fossil fuels have a great potential for environmental pollution, causing impacts on human health, animal life, forests, soil and water quality. This study aimed to evaluate the biodegradation of diesel and biodiesel by fungi Rhizopus ssp., Mucor ssp., Aspergillus ssp., Penicillium ssp and Fusarium ssp in soils contaminated with diesel and biodiesel through a plant bioindicator. This is an experimental laboratory study, with hypothetical-deductive analysis. The methodologies used establish the conditions for obtaining biodiesel samples, the determination of physical-chemical parameters of diesel and biodiesel samples, the determination of oxidative stability of the samples, and the phytotoxicity analyses based on the description of the germination rate of Vigna unguiculata (L.) Walp seeds, the net assimilation rate, the leaf area index and the crop growth rate. The data were obtained by comparative calculations between treatment groups and correlation between LAI and IP. The results show widely varied values ​​among the samples: 0.0-0.96/h for BV, 0.0-3.53/h for BG, 0.0-5.30/h for BF and 0.0-25.08/h for DF as order of efficiency by the Rancimat method. In the phytotoxicity analyses, the differences in the median values ​​between the treatments are greater than would be expected for the case, a germination rate of 100% was observed for S.C, 50% for BF, 25% for BV, 25% for BVR and 0% for the other treatments in the period of 14 days, where p < 0.05. In the growth analyses of Vigna unguiculata (L.) Walp as a bioindicator, maximum values ​​for TAL were observed in the DFR treatments with 2,733 g.m -2 .week -1 for 30 days and BV with 2,179 g.m -2 .week -1 for 60 days; for IAF in the BGR treatments with 0.367 for 30 days and BGR with 0.656 for 60 days and for TCC it showed fluctuations in the BFR, BVR and BGR treatments with 0.419, 0.460 and 0.471 g.m -2 .week -1 respectively for 30 days up to 60 days an increase was observed in the same treatments. The results showed high efficiency in the biodegradation of the biodiesel samples, and the correlation results observed between IAF and PI reinforce the fact that the diesel samples are resistant to the oxidation process. This fact is related to the interfacial mechanism of enzyme activation, types of enzymes specific to the substrate and the catalytic mechanisms involved(TRADUÇÃO NOSSA)