明亮发光杆菌培养的响应面优化及其对常见金属离子的毒性评价研究

Increasing awareness and concerns about the toxicity of metals is driving demand for a higher sensitivity biological toxicity detection method. In this study, the concentration of main components in traditional medium of Photobacterium phosphoreum was optimized by Response Surface Methodology (RSM) with the luminescent intensity as response value. The optimum medium composition was NaCl (25.00 g·L^-1), Tryptone (4.010 g·L^-1), yeast extract (1.200 g·L^-1) and glycerin (2.475 g·L^-1). After incubation for 14 h in the optimum culture, the biomass (the value of OD₅₉₅ was 0.85) was increased by 5%. Based on the optimization of the medium components, the influence of inoculation amount, temperature and pH value on luminescent intensity was carried out by single factor analysis. It was concluded that luminescent intensity would not be affected significantly under the conditions of 1% inoculation amount (the initial OD₅₉₅ was 0.003), temperature of 22~25 ℃ and pH value of 6~8. Subsequently, the acute toxicity of common metal ions was evaluated in the optimized culture conditions, and the results showed that except Fe²⁺, Zn²⁺, K⁺, the sensitivity of P. phosphoreum to other heavy metal ions was improved, among which the sensitivity to Cr⁶⁺ increased most significantly with the detection limit increasing from 1.00 mg·L^-1 to 0.15 mg·L^-1 and IC₅₀ decreasing from 7.818 mg·L^-1 to 4.133 mg·L^-1. The improved detection limit could better meet the requirements of different industries for the detection limit of Cr⁶⁺. In this study, a method to improve the toxicity sensitivity of common metals by optimizing the culture composition and condition was proposed.