La. Launen et al., Optimization of pyrene oxidation by Penicillium janthinellum using response-surface methodology, APPL MICR B, 51(4), 1999, pp. 510-515
At present, there is little information on the optimization of the degradat
ion of polycyclic aromatic hydrocarbons (PAH) by deuteromycete filamentous
fungi, a reaction catalyzed by cytochrome P450 monooxygenases. We utilized
response-surface methodology to determine the optimal growth conditions for
the oxidation of the PAH pyrene by Penicillium janthinellum SFU403, with r
espect to the variables glucose concentration, nitrate concentration and bi
oconversion time. Models were derived for the relationship between the vari
ables tested and the level of the pyrene oxidation products, 1-pyrenol (1-P
Y) and pyrenequinones (PQ). Production of 1-PY and PQ were optimized by the
same glucose and nitrate concentrations: 2.5% glucose and 1.5% sodium nitr
ate. The optimized I-PY and PQ bioconversion times were 71 h and 73 h respe
ctively. These conditions improved the yield of 1-PY by fivefold and PQ wer
e more than 100-fold higher than the baseline levels obtained in this study
. The optimized PQ yield represented 95% of the initial pyrene, thus the to
tal optimised pyrene bioconversion to 1-PY and PQ was approximately 100%. C
oncentrations of glucose exceeding 4.0% repressed pyrene hydroxylation. Pyr
ene hydroxylation occurred almost exclusively during the deceleration phase
of culture growth.