Biodegradation of used lubricating and diesel oils by a new yeast strain <i>Candida viswanathii</i> KA-2011

Abstract

Disposal of the automotive lubricating oil after usage can cause environmental hazards. This study aimed to isolate a microbial isolate is that able to biodegrade lubricating oil effectively. A new yeast strain, identified by 18S-rRNA gene sequencing as Candida viswanathii KA-201l, was isolated from used lubricating oil, showed high biodegradation efficiency for different used lubricating oils. Capability of this isolate to degrade different high and low molecular weight hydrocarbons, castor oil, diesel oil and grease was tested. It showed high degradation efficiency for most of the tested compounds. The biodegradation products were analyzed by gas chromatography-mass spectroscopy (GC-MS) in most cases. The biodegradation efficiency under high osmotic pressure was studied. It effectively biodegrade lubricating and diesel oils (58.6 and 93.9%, respectively) at 6% salt concentration after four days only. C. viswanathii KA-2011 can be effectively used for removal of lubricants, diesel or vegetative oils pollution from soil, wastewater and sea water. Use of C. viswanathii KA-2011 in the bioremediation of lubricant or gasoline contaminated sea-water save the aquaculture from these pollutants, as well as it open new horizons in using of contaminated soil and wastewater in agriculture.

Keywords: Lubricating oils, diesel oil, biodegradation, Candida viswanathii