Redução da carga poluidora de vinhaça de soja utilizando linhagens de Cupriavidus necator

Abstract

The effluent vinasse , soybean obtained by the process of recovery of alcohol from molasses , soybean has a high chemical oxygen demand ( COD) and high toxicity and can not be treated as a common waste effluent . By environmental problems and complications that can generate wastewater at the plant , is a new challenge that the choice for your treatment. Daily in Brazil, are obtained 10,000 L of ethanol to generate a daily volume of 220,000 L of soybean vinasse, in the only producing ethanol plant from soybean processing. The prevalence of this effluent in the environment represents a new central basis for research and studies related to environmental management. This work was developed to evaluate the reduction of the pollution load in soybean vinasse. Two treatments were tested (culture medium) using two strains of the genus Cupriavidus, including NRRL B - 2804 and NRRL B - 4383 and a strain of Pseudomonas oleovorans NRRL B -778 . The COD of vinasse, soybean was 155.18 gL-1 . It was conducted a preliminary study in soybean vinasse concentrations and evaluated the parameters such as biomass production in dry matter content, temperature and cell growth of microorganisms suitable for use. Treatments were applied and conducted in two culture media MC1 and MC2 using nonata tests in 500 mL Erlenmeyer flask with 150 mL capacity of culture medium for each finned treatment. The cultures were prepared with soybean vinasse diluted to 30%, modified nutrient broth supplemented with hydrolyzed rice husk, and MC1 was distinguished from the MC2 by subtracting the mineral medium (MM) of its composition. At the end of the study, two strains were selected C. necator NRRL B – 2804, NRRL B – 4383 respectively and 36 experimental units were prepared. The results of COD decrease and biomass formation in MC1 and MC2 were evaluated statistically by Tukey test and Levene using ANOVA for discrimination means and verification of homogeneity among treatments. The maximum reduction of COD obtained for MC1 and MC2 inoculated with the strain C. necator NRRL B- 2804 , respectively was 72% and 65 % of removal for cultivation in orbital shaker at 180 rpm, 30°C within the initial COD before vinasse treatment. The medium inoculated with strain MC2 C. necator NRRL B- 4383 was selected and fermented in a bioreactor - fermenter BIO - TEC 7.5 L for 72 h with 66% of COD removal under the same conditions. The presence of polyhydroxyalkanoates (PHAs) derived from biomass in the medium inoculated with the strain MC2 C. necator NRRL B - 2804 was identified by the fusing temperature of 173°C confirmed in the literature. The COD reduction obtained for the soybean vinasse using culture media containing industrial waste, proved to be a promising treatment for new perspectives with a focus on environmental management, to the conditions applied in this study could be improved by optimization of the bioprocess used.