Effect of rhamnolipids on the biodegradation of m-dichlorobenzene in biotrickling filters: Performance and mechanism

• Published in: Journal of environmental management 2022-10, Vol.320, p.115951-115951, Article 115951
• Main Authors: Yang, Bairen, Wang, Jiajie, Wu, Menglei, Shang, Qingqing, Zhang, Hao
• Format: Article
• Language: English
• Subjects: Biofilm; Biotrickling filters; m-Dichlorobenzene; Microbial community; Rhamnolipids
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2022.115951

In this study, the effect of rhamnolipids (RL) on m-dichlorobenzene (m-DCB) removal and biofilm was investigated in two biotrickling filters (BTF) (BTF1: blank control; BTF2: RL addition). The critical micelle concentration (CMC) value of RL was 75.6 mg L−1, and the RL could significantly improve the solubilization of m-DCB. The results showed that the optimal concentration of RL was 180 mg L−1. The removal efficiency (RE) of m-DCB dropped by 42.4% for BTF1 no fed with RL and only 28.2% for BTF2 fed with RL when the inlet concentration increased from 200 to 1400 mg m−3 at an empty bed time (EBRT) of 60 s. RL increased the secretion of extracellular polymers (EPS) and the ratio of Protein/Polysaccharide, which improved the mass transfer of m-DCB to the biofilm. RL also had a facilitating effect on catechol-1,2-dioxygenase (C12O) enzyme activity. Furthermore, RL increased Zeta potential and facilitated microorganisms to form biofilm. The dominant microorganisms of microbial community were increased and the application of RL promoted the enrichment of them. [Display omitted] •Rhamnolipid increased the solubility of m-Dichlorobenzene.•The performance of biotrickling filters was significantly enhanced by rhamnolipid.•Rhamnolipid increased the contents of extracellular polymers, enzyme activity and Zeta potential of the biofilm.•The application of rhamnolipid promoted the enrichment of dominant microorganisms.