MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, PR China.
MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, PR China; Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu Province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou, 730020, PR China.
Environ Pollut. 2021 Nov 15;289:117885. doi: 10.1016/j.envpol.2021.117885. Epub 2021 Aug 2.
Phytoremediation causes a large quantity of phytoremediation residues rich in heavy metals (HMs). This kind of plant residue can be used as a substrate for anaerobic digestion (AD) to reduce the content of HM-containing biomass, but high concentrations of HMs will inhibit the digestion efficiency and reduce the conversion efficiency of plant residues. Bioaugmentation may be an effective method to improve the degradation efficiency and methane yield of plant residues rich in HMs. In this study, a cellulose-degrading anaerobic bacteria Paracoccus sp. Termed strain LZ-G1 was isolated from cow dung, which can degrade cellulose and simultaneously adsorb Cd. The Cd (10 mg/L)-adsorbtion efficiency and cellulose (463.12 g/kg)-degradation rate were 65.1 % and 60.59 %, respectively. In addition, using the strain LZ-G1 bioaugmented Cd-containing plant residues and cow manure mixed AD system, the system's biogas and methane production significantly increased (98.97 % and 142.03 %, respectively). During the AD process, the strain LZ-G1 was successfully colonized in the digestion system. Furthermore, the microbial community analysis revealed that LZ-G1 bioaugmentation alleviates the toxicity of free Cd to the microbial community in the AD system, regulates and restores the archaea genus dominant in the methanogenesis stage, and restores the relative abundance of dominant bacteria associated with biomass hydrolysis. The restoration of the microbial community increased the biogas yield and methane production rate. Thus, bioaugmentation provides an easy and a feasible method for the actual on-site treatment of HM-rich phytoremediation residues.
植物修复会产生大量富含重金属（HM）的植物修复残留物。这种植物残渣可以用作厌氧消化（AD）的基质，以降低含 HM 生物质的含量，但高浓度的 HM 会抑制消化效率并降低植物残渣的转化效率。生物增强可能是提高富含 HM 的植物残渣降解效率和甲烷产量的有效方法。在这项研究中，从牛粪中分离出一株纤维素降解厌氧细菌 Paracoccus sp.，命名为 LZ-G1 菌株，它可以降解纤维素并同时吸附 Cd。Cd（10mg/L）的吸附效率和纤维素（463.12g/kg）的降解率分别为 65.1%和 60.59%。此外，在含有 Cd 的植物残渣和牛粪混合 AD 系统中使用 LZ-G1 菌株进行生物增强，系统的沼气和甲烷产量显著增加（分别为 98.97%和 142.03%）。在 AD 过程中，LZ-G1 菌株成功定殖于消化系统中。此外，微生物群落分析表明，LZ-G1 生物增强缓解了 AD 系统中游离 Cd 对微生物群落的毒性，调节并恢复了产甲烷阶段中主要的古菌属，并恢复了与生物质水解相关的优势细菌的相对丰度。微生物群落的恢复提高了沼气产量和甲烷产生率。因此，生物增强为富含 HM 的植物修复残留物的实际现场处理提供了一种简单可行的方法。
