Biodegradação de querosene por Candida lipolytica em água do mar

Abstract

Spills of oil and oil products, such as kerosene and diesel in seawater are cause for concern worldwide due to serious effects caused to the marine and coastal environment. The rate of biodegradation of hydrocarbons in sea water is affected by many physical, chemical and biological parameters, including the number and diversity of endogenous microorganism, the conditions for microbial degradation activity (presence of nutrients, oxygen and favorable conditions pH and temperature), the quantity, quality and bioavailability of contaminants and characteristics of sea water. In this work, two 24 full factorial designs were carried out to analyze the influence of pH (6, 10 and 14) and concentrations of kerosene and nutrients (ammonium sulfate and potassium phosphate monobasic) on degradation of kerosene and production bioemulsifiers/biosurfactants by Candida lipolytica UCP 0988 in seawater. The seawater used in the tests was collected near the beach in Suape Harbor, Pernambuco, Brazil. The biodegradation tests were performed at the temperature of 28 ° C, on a rotatory shaker at 200 rpm, for 5 days. The yeast C. lipolytica UCP 0988 was able to use kerosene (10%, 20% or 30% v / v) and grows in seawater, supplemented with ammonium sulfate and potassium phosphate monobasic, producing biosurfactants with high emulsification activity. The phytotoxicity of biodegradated samples collected with 5 days was evaluated using seed germination and root elongation techniques with Makassar beans (Vigna ungiculata (L.) Walp.).