Effects of Exhaustion Gases from Biodiesel Blends on the Lichen Cladonia verticillaris: A Complimentary Evaluation

Abstract

The objective of this study was to evaluate the effects of gases emitted by blends of biodiesel with petroleum diesel at intermediate concentrations (between 10 % and 40 %) on the biochemistry of the lichen Cladonia verticillaris (Raddi) Fr. Samples of the respective species were exposed to the gases during a period of sixty minutes, using a stationary engine, with blends of 20 % (B20), 25 % (B25) and 30 % (B30) of biodiesel, from the oil from cotton, to petroleum diesel. In the period of 30, 60 and 90 days, the concentrations of primary metabolites (chlorophylls and pheophytins) and secondary (protocetraric acid and fumarprotocetraric acid) were determined. A control group was used for comparison purposes. The gases emitted during the combustion process were also evaluated at three times (0 minutes, 30 minutes and 60 minutes). The results did not show significant differences for chlorophylls, when all treatments and control materials were compared, however, variations were observed for the other metabolites. The concentration of protocetraric acid was higher compared to fumarprotocetraric acid, indicating that there were blocks in the synthesis of the metabolic pathway. Cluster analysis showed that for groups B20 and B25, pheophytins are related to CO2, while for B30 their chlorophylls are related to NO2. The results demonstrate that the respective mixtures do not affect the integrity of the species, confirming the recommendation to use mixtures of biodiesel with petroleum diesel up to 40 %. Keywords: biofuels, environmental impact, living organisms, lichen substances, biomonitoring.