Bacillus velezensis P#02 simultaneously produced surfactin and polyglutamic acid (PGA). Among the different culture media studied, the one containing corn steep liquor (100 mL/L), glucose (10 g/L), and glutamic acid (10 g/L) as sole ingredients (CSLGGlut(10)) offered the best results regarding biosurfactant and biopolymer production. Although biosurfactant production occurred both under shaking and static conditions, significant biopolymer production occurred only in static cultures. Using the culture medium CSLGGlut(10), 910 ± 20 mg surfactin/L and 9.8 ± 0.2 g PGA/L were produced. Surfactin was synthetized as a mixture of five different homologues (fatty acid chains ranging between C12 and C16), being the most abundant C14 and C15surfactin. Surfactin reduced the surface tension up to 29 mN/m, with a critical micelle concentration of 52 mg/L, and exhibited a significant emulsifying activity. B. velezensis P#02 PGA, which molecular weight was around 229 kDa, displayed a nonNewtonian shearthinning profile, achieving apparent viscosity values around 3800 mPa s in aqueous solution, with a predominant viscous behavior. Accordingly, B. velezensis P#02 is a promising strain for the simultaneous production of PGA and surfactin using the waste stream corn steep liquor.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) for financial support under the scope of the strategic funding of UIDB/04469/2020 unit, with DOI 10.54499/UIDB/04469/2020, and LABBELS – Associate Laboratory in Biotechnology, Bioengi neering and Microelectromechanical Systems, LA/P/0029/2020. Eduardo J. Gudina˜ thanks FCT for the research contract DL 57/2016/CP1377/CT0039 (DOI 10.54499/DL57/2016/CP1377/CT0039). Ricardo Dias would also like to acknowledge FCT for the Scientific Employment Stimulus grant (2021.01830.CEECIND/CP1662/CT0013, DOI 10.54499/2021.01830.CEECIND/CP1662/CT0013).info:eu-repo/semantics/publishedVersio
