Biodegradation of diesel oil hydrocarbons enhanced with Mucor circinelloides enzyme preparation

• We use complex biological diesel oil degradation method.
• We examine immobilized in situ M. circinelloides enzymes as an agent for enhanced biodegradation.
• Efficiency of enzyme enhanced biodegradation increased in about 20–30 %.
• M. circinelloides enzymes have significant influence on emulsifying and respiratory activity of bacteria.

The aim of the study was to use immobilized in situ Mucor circinelloides (MC) enzymes preparation as an agent for enhanced microbial hydrocarbons biodegradation. It is a new element of complex biological degradation of diesel oil hydrocarbons (8% v/v) performed by bacterial consortia (Gordonia alkanivorans S7 (S7), Achromobacter xylosoxidans G21 (G21), Pseudomonas sp. A34 (A34)). After 14 days of biodegradation experiments, addition of M. circinelloides enzyme preparation not only increased the efficiency of hydrocarbons degradation in about 20 %–30 % compared to samples without the preparation, but also resulted in higher metabolic activity of microorganisms (higher respiratory activity, 30% decrease in critical oxygen concentration). The use of M. circinelloides enzyme preparation has significant influence on the emulsifying activity of the strains, which is very important in case of utilization of hydrophobic substances, such as hydrocarbons. Values of the parameter were relatively higher in the presence of the preparation (trail with A. xylosoxidans G21 and MC OD500 = 1.3 ± 20.8 × 10−3 at the same time trail with A. xylosoxidans G21 OD500 = 0.925 ± 0.5 × 10−3). Data obtained with GC chromatographic analysis confirmed the positive impact of fungal enzyme preparation on the process of diesel oil hydrocarbons degradation.