Fang Xilin, Cai Zeming, Wang Xiaocui, Liu Ziyu, Lin Yongkang, Li Minqian, Gong Han, Yan Muting
College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
Microorganisms. 2024 Oct 2;12(10):2005. doi: 10.3390/microorganisms12102005.
With the rapid growth of global plastic production, the degradation of microplastics (MPs) has received widespread attention, and the search for efficient biodegradation pathways has become a hot topic. The aim of this study was to screen mangrove sediment and surface water for bacteria capable of degrading polyethylene (PE) and polypropylene (PP) MPs. In this study, two strains of PE-degrading bacteria and two strains of PP-degrading candidate bacteria were obtained from mangrove, named sp. strain GIA7, strain GIA17, sp. strain GIB8, and strain GIB10. The results showed that the degradation rate of the bacteria increased gradually with the increase in degradation time for 60 days. Most of the MP-degrading bacteria had higher degradation rates in the presence of weak acid. The appropriate addition of Mg and K was favorable to improve the degradation rate of MPs. Interestingly, high salt concentration inhibited the biodegradation of MPs. Results of scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier-transform infrared spectroscopy (FTIR) indicated the degradation and surface changes of PP and PE MPs caused by candidate bacteria, which may depend on the biodegradation-related enzymes laccase and lipase. Our results indicated that these four bacterial strains may contribute to the biodegradation of MPs in the mangrove environment.
随着全球塑料产量的迅速增长，微塑料（MPs）的降解受到广泛关注，寻找高效的生物降解途径已成为热门话题。本研究的目的是从红树林沉积物和地表水中筛选能够降解聚乙烯（PE）和聚丙烯（PP）微塑料的细菌。在本研究中，从红树林中获得了两株PE降解菌和两株PP降解候选菌，分别命名为sp.菌株GIA7、菌株GIA17、sp.菌株GIB8和菌株GIB10。结果表明，在60天的降解时间内，细菌的降解率随降解时间的增加而逐渐升高。大多数MP降解菌在弱酸存在下具有较高的降解率。适当添加Mg和K有利于提高MPs的降解率。有趣的是，高盐浓度会抑制MPs的生物降解。扫描电子显微镜（SEM）、原子力显微镜（AFM）和傅里叶变换红外光谱（FTIR）结果表明，候选细菌导致了PP和PE MPs的降解及表面变化，这可能取决于与生物降解相关的漆酶和脂肪酶。我们的结果表明，这四株细菌菌株可能有助于红树林环境中MPs的生物降解。
