Marta Martins Neto

Biodegradation of Diethylketone by Penicillium sp. and Alternaria sp. - A Comparative Study Biodegradation of Diethylketone by Fungi

Two contaminating fungi were isolated from a bioreactor containing diethylketone and Streptococcus equisimilis, subsequently characterized at molecular level and identified as belonging to the Alternaria and Penicillium genera. The ability of these fungi to biodegrade DEK is evaluated. The kinetic parameters are estimated using four growth kinetic models for biodegradation of organic com- pounds available in literature. The experimental data for Alternaria sp. and Penicillium sp. was found to be better fitted by the Haldane and the Luong respectively. Biodegradation rate kinetics was evalu- ated using zero-order, pseudo-first order, pseudo-second order and three-half order models. The pseudo-second-order model was found suitable for all the concentrations of DEK tested for the biodeg- radation assays using Penicillium sp. whereas for the Alternaria sp. this model just describes properly the assays with ini- tial concentrations of DEK higher than 0.5 g/L. The percentage of biodegraded DEK were approximately 100%, for all the initial concentrations tested.

Biodegradation of diethylketone by two fungi

Two morphologically different fungi (one green and one white) from contaminated bioreactors with an aqueous solution of diethylketo ne and Streptococcus equisimilis were isolated and characterized at molecular level by sequencing the amplified ITS region. The ITS region sequence showed 99% match with Alternaria genera for the green fungi and 99% match with the Penicillium genera for the white fungi. The performance of thes e two fungi to biodegrade different concentrations of diethylketone from aqueous solutions was evaluat ed. The biodegradation of diethylketone was studied for an initial diethylketone concentration ranging from 0.5 to 4g/L in a batch mode of operation. The biodegradation rate found for both f ungi followed the pseudo-second order kinetics for initial concentrations higher than 0.5 g/L and the resulting kinetic parameters are reported. The remo val percentages obtained were approximately 100%, for all the initial concentrations tested.