CHEMICAL ENGINEERING TRANSACTIONS VOL. 37, 2014 A publication of The Italian Association of Chemical Engineering www.aidic.it/cet Guest Editors: Eliseo Ranzi, Katharina Kohse- Höinghaus Copyright © 2014, AIDIC Servizi S.r.l., I SBN 978-88-95608-28-0; I SSN 2283-9216 Strategy of Using Waste for Biosurfactant Production Through Fermentation by Bacillus Subtilis Brunno F. Santos* a , Alexandre N. Ponezi b , Ana M. F. Fileti a a *School of Chemical Engineering, Department of Chemical Systems Engineering, University of Campinas (UNICAMP) 13083-970, Campinas/SP, Brazil b Research Center for Chemistry, Biology and Agriculture (CPQBA), University of Campinas (UNICAMP), 13081-970, Campinas/SP, Brazil. brunnofdsantos@gmail.com Recently, the biosurfactant production has been growing up, because this substance has amphiphilic nature with high emulsifying and surface interaction. They are produced through metabolism of microorganisms and many applications are mentioned in industry (chemical, food, pharmaceutical etc.). However, the production is compromised by the use of expensive synthetic substrates. A viable alternative is resort to substrates of waste sources. This study aims to identify optimally biosurfactant production through fermentation by Bacillus subtilis using alternative substrates based waste (Glycerin from biodiesel production process, beet peel and corn steep liquor). To set the waste concentration were used design of experiments and process optimization strategies, aided by STATISTICA 7 software. It was decided use in a Central Composite Rotational Delineation 2 3 , evaluating the responses of Emulsifying Index after 24 h (E 24 ) and crude biosurfactant (CB). The optimum point was validated in triplicated. Experiments in scale up were performed to confirm the selected conditions. With these results, it was possible to determine the concentration of waste able to provide a good E 24 and BC values. 1. Introduction Surfactants are wide used in several industries around the world, due the molecular characteristic: polar and nonpolar. This particularity ensures the surfactant interfacial properties, in other words, wettability agents that lower the surface tension of a liquid. A surfactant molecule is capable of forming stable emulsions and is present in formulations of food, pharmaceutical products, petroleum compounds, cosmetic, water and soil remediation, textile and some processes. The bulk of surfactant manufacturing is dedicated to those materials that are blended into commercial detergent formulations (Schramm et al. 2003). So many applications come together disadvantages, such as high toxicity and low degradability. In this context, alternatively arises natural surfactant or biosurfactant, produced by metabolism of microorganism (bacteria, yeast and mold). The biosurfactants have the same characteristics of the surfactants by chemical sources. For instance, biosurfactant produced by Candida lipolytica was applied in the remediation of heavy metals (have removed around 96 % of Zn and Cu and decreased the concentration of Pb, Cd, Fe) (Rufino et al., 2012). The biosurfactants are more effectives than surfactants, what means that lower amount of biosurfactant may be able to have same performance. The use of biosurfactant is not widely encouraged yet, because of the cost involved in production and purification. Many researches choose use waste like medium of fermentation to biosurfactant production. Fontes et al. (2012) used crude glycerine and clarified cashew apple juice were applied as feedstocks for the microbial surfactant synthesis by Yarrowia lipolytica. It was studied two waste: corn steep liquor and ground–nut oil refinery as low cost nutrients for the production of a biosurfactant by Candida sphaerica (UCP 0995) (Luna et al., 2012). Cassava flour wastewater were tested such as culture media for biosurfactant production by Bacillus sp. And results showed a surface tension of 59 to 26 mN/m (Nitschke and Pastore, 2004). DOI: 10.3303/CET1437122 Please cite this article as: Santos B., Ponezi A., Fileti A.M.F., 2014, Strategy of using waste for biosurfactant production through fermentation by bacillus subtilis, Chemical Engineering Transactions, 37, 727-732 DOI: 10.3303/CET1437122 727