Production and Evaluation of Biosurfactant by Serratia marcescens UCP 1549 Using Industrial Wastes.

Aims: Biosurfactants are surface-active agents of microbial origin that have a property of lowering the surface tension between two liquids. This study aimed to the production of biosurfactant by Serratia marcescens UCP 1549 in medium containing agro-industrial wastes for making possible its industrial application in the near future and to propose its environmental applications. Place and Duration of Study: Center of Science and Technology from State University of Paraíba - UEPB, Campina Grande – PB, Brazil and Nucleus of Research in Environmental Sciences and Biotechnology (NPCIAMB), Catholic University of Pernambuco - UNICAP, Recife-PE, Brazil between June 2011 and July 2012. Methodology: According to the proposed factorial design, the culture medium was developed and used for the production of biosurfactant and incubated at 28ºC, 155 rpm during 48 h. The produced biosurfactant was evaluated by emulsifying index, emulsifying activity and surface tension using hydrophobic substrates as vegetable oils after frying, nhexadecane and diesel. Results: The best results for emulsification index were found between 79.92 and 100% of emulsification and for activity were values between 2.304 and 5.000 EA (emulsification activity) using vegetable oil after frying as substrate. In relation of the surface tension, the best value obtained was 33.10mN/m in the condition of the central point of the experimental design. Conclusion: The results show that Serratia marcescens UCP 1549 was capable of producing a biosurfactant with emulsifying property from industrial wastes in the studied conditions in this work.

Uso do meio sólido para screening de atividade amilolítica em Aspergillus niger / Use of solid medium for amylolitic screening in Aspergilus niger

This paper describes the correlations between the activity of amylase in A. niger, using two solid medium. the detection amylase was carried out incubating in triplicate four straints of A. niger, in both solid medium containing starch as substrate. The amylolytic activity was measured using the relation between the diameter of colony and halo of degradation formed. the results suggest that NA (Nutritive agar containing 0.2% of starch) produced the best activity. The strains indicated the following results: Q2 a (1.56 cm ñ 0.16). Q2 b (1.24 cm ñ 0.24) Q14 (1.1 cm ñ 0.18), and Q10 (negative). The basic starch medium showed poor results probably by absence of cystein in the composition