关键词: 绿色木霉, 草酸青霉, 重金属耐性, 生物吸附

Abstract: [Objective]The study aims to research biosorption and tolerance of Hg²⁺, Zn²⁺, Cu²⁺, Pb²⁺ by Penicillium oxalicum and Trichoderma viride, and hopes to provide a scientific reference for its soil remediation.[Method] The heavy metal-tolerance of fungi was evaluated by measuring the growth inhibition rate of the two fungal varieties and the medial lethal concentration (EC₅₀) of heavy metal ions. Firstly, a certain amount of mycelium balls were put into the heavy metal ion solution of known concentration. A few of hours later, the ion concentration was analyzed, and then the heavy metal adsorption efficiency and adsorption quantity were calculated, and the adsorption process was fitted with a function model.[Result]The results showed that biomass of the two strains decreased with increasing concentration of heavy metals, and the process could be divided into two stages. When the metal ions concentration was under 200 mg·L^-1, the biomass did not obviously decline or slightly increased. When the concentration was higher than critical value (about 400 mg·L^-1), the biomass dropped rapidly. The EC₅₀ value of strain lys2015f1 in Hg²⁺, Zn²⁺, Cu²⁺, and Pb²⁺ solution was 158.07, 464.02, 229.33, and 209.59 mg·L^-1, and it for strain lys2015f5 was 580.47, 572.88, 231.85, and 2 284.01 mg·L^-1. Thus, the tolerance degree of strain lys2015f1 to heavy metals was in the order of:Zn²⁺ > Cu²⁺ > Pb²⁺ > Hg²⁺, and the tolerance level of strain lys2015f5 was Pb²⁺ > Hg²⁺ > Zn²⁺ > Cu²⁺. The adsorption process was more fitted to the pseudo-second-order kinetic model. According to the model rate constant k₂ value, the adsorption rate of two strains was obtained, and the two strains had the same order in adsorption rate for those metal ions of Pb²⁺ > Hg²⁺ > Cu²⁺ > Zn²⁺. The theoretical value of the maximum adsorptions to (Hg²⁺, Zn²⁺, Cu²⁺, Pb²⁺) from this model for lys2015f1 was 37.12, 14.63, 16.62, and 107.31 mg·g^-1, and for lys2015f5 was 47.12, 16.50, 25.78, and 201.22 mg·g^-1. The rate limiting step of adsorption was controlled by chemical reactions. In the same conditions, the order of two strains for heavy metal adsorption rate was Hg²⁺ > Cu²⁺ > Zn²⁺ > Pb²⁺.[Conclusion]The two strains have high heavy metal tolerance and adsorption. Combined with the functions of biological control, plant growth, degrading soil organic matter etc, the strains should have high potential abilities in remediation of heavy metals pollution.

Key words: Penicillium oxalicum, Trichoderma viride, heavy metal resistance, biosorption