Biofertilizers have been widely used in many countries for their benefit to soil biological and physicochemical properties. A new microbial biofertilizer containing Phanerochaete chrysosporium and Bacillus thuringiensis was prepared to decrease nicotine content in tobacco leaves by regulating soil nitrogen supply. Soil NO-N, NH-N, nitrogen supply-related enzyme activities, and nitrogen accumulation in plant leaves throughout the growing period were investigated to explore the mechanism of nicotine reduction. The experimental results indicated that biofertilizer can reduce the nicotine content in tobacco leaves, with a maximum decrement of 16-18 % in mature upper leaves. In the meantime, the total nitrogen in mature lower and middle leaves increased with the application of biofertilizer, while an opposite result was observed in upper leaves. Protein concentration in leaves had similar fluctuation to that of total nitrogen in response to biofertilizer. NO-N content and nitrate reductase activity in biofertilizer-amended soil increased by 92.3 and 42.2 %, respectively, compared to those in the control, whereas the NH-N and urease activity decreased by 37.8 and 29.3 %, respectively. Nitrogen uptake was improved in the early growing stage, but this phenomenon was not observed during the late growth period. Nicotine decrease is attributing to the adjustment of biofertilizer in soil nitrogen supply and its uptake in tobacco, which result in changes of nitrogen content as well as its distribution in tobacco leaves. The application of biofertilizer containing P. chrysosporium and B. thuringiensis can reduce the nicotine content and improve tobacco quality, which may provide some useful information for tobacco cultivation.

Phanerochaete chrysosporium has been identified as an effective bioremediation agent for its biosorption and degradation ability. However, the applications of P. chrysosporium are limited owing to its long degradation time and low resistance to pollutants. In this research, nitrogen-doped TiO2 nanoparticles were loaded on P. chrysosporium to improve the remediation capacity for pollutants. The removal efficiencies were maintained at a high level: 84.2% for Cd(II) and 78.9% for 2,4-dichlorophenol (2,4-DCP) in the wide pH range of 4.0 to 7.0 in 60 h. The removal capacity of immobilized P. chrysosporium loaded with nitrogen-doped TiO2 nanoparticles (PTNs) was strongly affected by the initial Cd(II) and 2,4-DCP concentrations. The hyphae of PTNs became tight, and a large amount of crystals adhered to them after the reaction. Fourier transform infrared spectroscopy showed that carboxyl, amino, and hydroxyl groups on the surface of PTNs were responsible for the biosorption. In the degradation process, 2,4-DCP was broken down into o-chlorotoluene and 4-hexene-1-ol. These results showed that PTNs is promising for simultaneous removal of Cd(II) and 2,4-DCP from wastewater.

Microorganisms need to resist the hazards posed by heavy metals during the process of metal adsorption. Phanerochaete chrysosporium is a fungus that is efficiently used for heavy‐metal biosorption in wastewater treatment. Extraction and analysis of proteins induced by heavy metals can help to understand the regulatory mechanisms of P. chrysosporium in wastewater treatment. In this study, P. chrysosporium was exposed to 50 μM cadmium nitrate. A maximum cadmium adsorption capability of 77.1 mg/g dry biomass was found after 65 h, which was accompanied by a relatively higher protein concentration. After separation of the culture fluid proteins by two‐dimensional difference gel electrophoresis (2D‐DIGE), three differentially expressed proteins were detected from 17 spots. By using 2D‐DIGE, followed by matrix‐assisted laser desorption/ionization time‐of‐flight/time‐of‐flight mass spectrometry (MALDI‐TOF/TOF MS), glutathione S‐transferase, glyceraldehyde‐3‐phosphate dehydrogenase, and malate dehydrogenase were identified. All three enzymes play important roles in the oxidative stress caused by cadmium.