Benzo(a)pyrene (BaP) is a five-ring polycyclic aromatic hydrocarbon produced by the incomplete combustion of organic materials. It is one of the priority pollutants listed by the US Environmental Protection Agency. This study describes a fungal isolate that is able to biodegrade benzo(a)pyrene. The filamentous fungus, isolated from leaves of Pterocarpus macrocarpus Kurz., was identified as a Fusarium sp. (strain E033). Fusarium sp. E033 was able to survive in the presence of benzo(a)pyrene concentrations up to 1.2 mM (300 mg L(-1)). Biodegradation experiments using 0.4 mM (100 mg L(-1)) benzo(a)pyrene demonstrated that Fusarium sp. E033 was able to degrade 65-70% of the initial benzo(a)pyrene provided, and two transformation products, a dihydroxy dihydro-benzo(a)pyrene and a benzo(a)pyrene-quinone, were detected within 30 days of incubation at 32 degrees C. The factors affecting biodegradation efficiency were also investigated. While increasing aeration promoted better fungal growth and benzo(a)pyrene biodegradation, increasing the glucose concentration from 5 to 50 mM had an adverse effect on biodegradation. Ethanol and methanol, provided at 5 mM to increase benzo(a)pyrene water solubility, increased the fungal biomass yield but did not promote degradation. The Fusarium sp. E033 isolated in this study can tolerate and degrade relatively high concentrations of benzo(a)pyrene, suggesting its potential application in benzo(a)pyrene bioremediation.
Fusarium solani NAN103 lipase was successfully overexpressed in Pichia pastoris using inducible expression system and constitutive expression system under the control of alcohol oxidase 1 promoter (pAOX1) and glyceraldehyde-3-phosphate dehydrogenase promoter (pGAP), respectively. Lipase obtained using the constitutive promoter showed the highest activity of 18.8 U/mg in 3 days of cultivation time. Optimal lipase activity was observed at pH 7.0 and 35 C using pnitrophenyl laurate as the substrate. Lipase activity was enhanced by Mn 2C , Ba 2C , Li C , Ca 2C , Ni 2C , CHAPS and Triton X-100 but was inhibited by Hg 2C , Ag C and SDS. The addition of 10% v/v of octanol, p-xylene, hexane and isopropanol increased lipase activity. Cultivation of lipase-expressing P. pastoris under pGAP in synthetic wastewater containing 1% w/v palm oil resulted in degradation of 87% of the oil within 72 h. P. pastoris expressing F. solani lipase from constitutive expression system has the potential to be used as an alternative microorganism for lipid degradation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.