Abstract
The sugar cane was first grown produce exported from Brazil during the colonial period. Nowadays the cultivation of cane sugar became relevant for its final inclusion of ethanol in the Brazilian energy matrix. Among the effluents generated in the sugar industry vinasse has high content of organic matter, coupled with nutrients such as nitrogen, phosphorus and potassium as well as minerals such as zinc, iron, manganese and others. These characteristics make it possible to use as a substrate in fermentation processes. The biosurfactants spite of its wide field of use in the environmental area when retrieving soil in the oil industry which is widely used in oil recovery wells and in the food industry and health, industrial production is restricted by the high cost of operations that involve your getting in that respect is very important to find alternatives to reduce these costs, using substrates that would be discarded in the environment or underutilized, leveraging content available carbon in these waste (solid or liquid) and minimizing the impact to the environment. The aim of this study was to use vinasse, biosurfactant production by Bacillus subtilis PC, in order to reduce production costs and minimize the environmental impacts generated by these effluents. In tests, the experimental design was the central planning central composite - DCCR, 2n with the number of independent variables equal to 3 (pH, concentration of vinasse and amount of inoculum), with replicas at the midpoint and axial points, using agitation 120 rpm and temperature 30 °C. Measurements were made of the Surface Tension (ST) using KSV Sigma 700 tensiometer by the Wilhelmy method, measures Emulsifying index (E24), using castor oil. The use of vinasse in the fermentation process for the production of biosurfactant without supplementation of salts and nutrients were obtained values of surface tension reduction on the order of 32 mN.m-1 and the emulsifying index E24 to 51.10 %. The operating conditions where the response variable (surface tension) reached the lowest value was 55 % (v/v) concentration of vinasse, 20.40 % (v/v) inoculum concentration, pH value 6.5. The experiment showed that the inoculum concentration had the greatest effect with respect to the data of ST. The vinasse presented potential as substrate for the production of biosurfactants.
