Isolation and identification of a high-efficiency phenol-degrading fungi and the preparation of its microbial inoculum

Abstract:

[Background] Phenolic wastewater is toxic, widespread and difficult to be decomposed. Biological treatment of phenolic wastewater has a broad application prospects due to its low cost and no secondary pollution. In the microorganisms that can degrade phenol, the fungi are more adaptable to the harsh environment than the bacteria. For the bottlenecks such as the short storage time of the fungal suspension and the difficulties for transport, preparation of microbial inoculum can improve cell viability and storage stability. [Objective] This paper tried to isolate an efficient phenol-degrading fungi, optimize the degradation performance and select the appropriate carrier for the preparation of its microbial inoculum. [Methods] Step-by-step domestication and purification was used to isolate the efficient phenol-degrading fungi. The species identification was carried out by ITS rDNA gene sequence analysis. The phenol degradation performance was further optimized by single factor experiments. Four different materials was used as carriers for the preparation of the microbial inoculum, then investigation of its preservation effect at different temperatures by dilution-plate method and phenol degradation were tested. [Results] An efficient phenol-degrading fungi named QWD1 was isolated and the identification proved it belonged to the Magnusiomyces capitatus genus. The optimal degradation conditions were as follows: (NH4)2SO4 as nitrogen source, inoculum concentration 15%, pH 7.0, temperature 35 °C, nitrogen source concentration 14 mmol/L. Under this condition, the removal rate of phenol was up to 97.15% in 28 hours. The optimum carrier for the preparation of the fungi was cavings, the storage temperature was 4 °C and the storage time can reach 90 days or even longer. The number of viable fungi was about 2.5×108 cfu/g, and the effect of phenol-degrading was good. [Conclusion] A high-efficiency phenol-degrading fungi was screened, for which the degradation performance was optimized, and it was prepared as the microbial inoculum, which provided new strain and theoretical support for the treatment of phenolic wastewater.

Key words:Degradation of phenol, Fungi, Microbial inoculum, Carrier