Pichia spp. yeasts from Brazilian industrial wastewaters: Physiological characterization and potential for petroleum hydrocarbon utilization and biosurfactant production

Pichia strains isolated from industrial wastewaters were physiologically characterized and tested for their potential for hydrocarbon utilization and biosurfactant production using hydrophobic and hydrophilic substrates. The emulsification index and growth curves were obtained to establish the relation between cell growth and this index. Pichia anomala CE009 grew in the range of 18 to 39°C and the optimum was 24°C. The strain was able to grow in NaCl concentrations between 2 and 15%, and pH values between 2 and 12. Pichia membranaefaciens CE015 grew at temperatures of 18 to 42°C and the optimum was 30°C. This strain grew in 2 to 10% of NaCl and pH from 2 to 12. Hexadecane, kerosene and diesel oil were used for growth but not for biosurfactant production, while glucose and glycerol were used for growth and biosurfactant production. Biosurfactant was detected during the exponential growth phase, with production peaks of 63% for P. anomala CE009 and 58% for P. membranaefaciens CE015. This study shows the potential of two Pichia strains for bioremediation exploitation under a wide range of environmental conditions. Key words: Emulsifying agents, Pichia anomala, Pichia membranaefaciens, glycerol.