Abstract: In this study, polylactic acid (PLA) and poly3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) were used as the external carbon source to explore release rule of the carbon source of PLA and PHBV under high, medium and low salinity in simulated seawater biofloc cultivation. The release rule is related to its influence on the water quality, microbial diversity and community structure in the aquaculture of marine biofloc. The results show that: PHBV carbon source is better than PLA carbon source, medium salinity is more conducive to the conversion of various nutrients. The mass concentration of salt and ammonia nitrogen is finally kept between 3.22~6.23 mg/L, and the phosphate is finally kept below 0.01 mg/L. In terms of the establishment of the biofloc system,the lower the salinity is, the faster the biofloc system is established. In the early stage of the experiment, in the low-salinity system,  PLA and PHBV had the lowest environmental average ammonia nitrogen concentration, which were 12.82 mg/L and 8.08 mg/L, respectively. The establishment of the biofloc system of the PHBV carbon source group was faster than that of the PLA carbon source group. In the establishment of microbial community, in the high-salinity system, Donghicola and Bacillus will cooperate to form a stable system. The study has shown that both PLA and PHBV carbon sources can be used in marine biofloc culture, and PHBV has a better effect.

Key words: BFT , mariculture , microbial community , salinity , water purification

摘要： 本研究以聚乳酸（PLA）和3-羟基丁酸-co-3-羟基戊酸共聚（PHBV ) 作为外加碳源，探究在模拟海水生物絮团养殖中高中低盐度下PLA与PHBV碳源释放规律以其对海水生物絮团养殖中水质、微生物多样性及其群落结构的影响。结果显示： PHBV碳源要优于PLA碳源，中盐度更有利于各种营养盐的转化，氨氮质量浓度最终保持在3.22~6.23 mg/L之间，磷酸盐最终保持在0.01 mg/L以下；在生物絮团系统建立方面，盐度越低越有利于生物絮团系统的快速建立，试验前期，低盐度系统中，PLA、PHBV环境平均氨氮质量浓度最低，分别为12.82 mg/L、8.08 mg/L，PHBV碳源组的生物絮团系统建立速度要快于PLA碳源组；在微生物群落建立中，在高盐度系统中会出现象牙白栖东海菌属（Donghicola）与芽孢杆菌属（Bacillus）相互配合形成稳定系统的情况。研究表明，PLA和PHBV两种碳源都可以用于海水生物絮团养殖中，且PHBV作用效果更佳。

关键词: 生物絮团, 海水养殖, 微生物群落, 盐度, 水质净化