Endophytic bacteria were isolated from Chlorella vulgaris and co-cultured with its host microalgae to determine whether this symbiotic system is suitable for purifying biogas and biogas slurry. Results showed that endophytic bacteria S395-1 and S395-2 belonged to different genera. Both strains promoted microalgae growth while improving photosynthetic performance, carbonic anhydrase activity, nutrient removal efficiency, and CO₂ fixation. The optimal bacteria (S395-2)-to-microalgae ratio and co-culture duration were 10:1 and 7 days. Under this condition, the growth rate and carbonic anhydrase activity were 0.196 ± 0.06 d^-1 and 31.24 ± 0.28 EU/cell, respectively. The symbiotic system had removal efficiencies of 88.29 ± 5.03%, 88.31 ± 4.29%, 88.21 ± 4.51%, and 68.13 ± 1.69% for chemical oxygen demand, nitrogen, phosphorus, and CO₂, respectively. These results will provide a framework for constructing a microalgal-bacterial consortium that can improve wastewater treatment and enhance biogas quality.

从寻常绿藻中分离出内生细菌，并与其宿主微藻共培养以确定这种共生系统是否适合纯化沼气和沼液。结果表明，内生细菌S395-1和S395-2属于不同属。两种菌株都促进了微藻的生长，同时提高了光合性能，碳酸酐酶活性，营养去除效率和CO ₂固定能力。最佳细菌（S395-2）与微藻的比例和共培养时间为10：1和7天。在此条件下，生长速率和碳酸酐酶活性为0.196±0.06 d ^-1和31.24±0.28 EU / cell。该共生体系对化学需氧量，氮，磷和CO _2的去除效率分别为88.29±5.03％，88.31±4.29％，88.21±4.51％和68.13±1.69％。这些结果将为构建微藻-细菌联盟提供框架，该联盟可以改善废水处理并提高沼气质量。