Soheil Ahmadi - Biotechnology Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, P.O.Box ۱۶۸۴۶-۱۳۱۱۴, Tehran, Iran
Parisa Hejazi - Biotechnology Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, P.O.Box ۱۶۸۴۶-۱۳۱۱۴, Tehran, Iran
Fereshteh Naeimpoor - Biotechnology Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, P.O.Box ۱۶۸۴۶-۱۳۱۱۴, Tehran, Iran

Rhamnolipid biosurfactants are attracting attention due to their low toxicity, high biodegradability, and good ecological acceptability. However due to severe foaming problems, biosurfactant production in submerged culture is difficult. Solid-state cultivation (SSC) is a promising alternative production method. Using SSC, it is possible to utilize renewable and low cost natural resources such as agricultural residues and byproducts of food industry. In this work, the effect of temperature and pH as cultivation conditions on a solid substrate consisting of corn bran and germ for biosurfactant production by Pseudomonas aeruginosa XD-10 was studied. It was shown that rhamnolipid production varies by temperature and pH with 30 °C and 7 being the favorable values, respectively. The best rhamnolipid production was found to be 2 g of rhamnolipid per kilogram of dry initial substrate (IDWS) which was obtained after 3 days. A maximum emulsion index of 75% was observed for the produced biosurfactant using diesel and gasoline.

Solid state cultivation, Rhamnolipid, Corn bran, Corn germ