College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China.
Demonstration Laboratory of Element and Life Science Research, Laboratory Centre of Life Science, College of Life Science, Nanjing Agricultural University, Nanjing, China.
J Basic Microbiol. 2022 Mar;62(3-4):518-529. doi: 10.1002/jobm.202100314. Epub 2021 Sep 6.
Algae-bacteria consortia have been proven effective in the removal of metal pollutants, but the effects of algal-bacterial ratio in the metal accumulation and resistance by this symbiotic system have not been systematically investigated. In this study, we set up consortia with various ratios of Chlorella salina-Bacillus subtilis, determined their growth, Cd accumulation, levels of intracellular glutathione (GSH), extracellular polysaccharide, phosphorus (P) in the culture medium, and functional groups of consortia after Cd treatments (0.1, 0.5, 1 mg L ) for 7 days. With the addition of B. subtilis in the C. salina culture, the dry weight and specific growth rate of the consortia significantly increased compared with C. salina alone, reaching 68.33 mg and 0.382 (mg L ) d respectively at the 1:4 algal-bacterial ratio with 1 mg L Cd treatment. Maximum Cd removal (51.66%) was also observed upon the same Cd exposure and algal-bacterial ratio. Cadmium was mostly taken up into cells at 1 mg L Cd whereas its adsorption dominated the accumulation when Cd was 0.1 and 0.5 mg L . The amounts of extracellular polysaccharides, GSH, and P of the symbiotic system were also increased by the bacterial addition. Besides, Fouriertransform infrared (FTIR) spectroscopy analysis showed that functional groups like N-H, O-H, and P-O-C were involved in the Cd complexation. Taken together, a higher bacterial ratio promoted the Cd accumulation and detoxification by the C. salina-B. subtilis consortia through intra- and extracellular processes.
藻菌共生体已被证明在去除金属污染物方面非常有效，但这种共生系统中藻菌比例对金属积累和抗性的影响尚未得到系统研究。在本研究中，我们设置了不同比例的盐藻-枯草芽孢杆菌共生体，确定了它们的生长、Cd 积累、细胞内谷胱甘肽（GSH）、细胞外多糖、培养基中磷（P）的水平，以及在 Cd 处理（0.1、0.5、1mg/L）7 天后的共生体功能基团。在盐藻培养中添加枯草芽孢杆菌后，与单独培养的盐藻相比，共生体的干重和比生长速率显著增加，在 1mg/L Cd 处理和 1:4 藻菌比时分别达到 68.33mg 和 0.382（mg/L）d。在相同的 Cd 暴露和藻菌比下，也观察到最大的 Cd 去除（51.66%）。在 1mg/L Cd 时，Cd 主要被细胞吸收，而在 0.1 和 0.5mg/L Cd 时，吸附则主导了积累。共生系统的细胞外多糖、GSH 和 P 的量也随着细菌的添加而增加。此外，傅里叶变换红外（FTIR）光谱分析表明，N-H、O-H 和 P-O-C 等功能基团参与了 Cd 的络合。总之，较高的细菌比例通过细胞内和细胞外过程促进了盐藻-枯草芽孢杆菌共生体对 Cd 的积累和解毒。
