Effect of konjac glucomannan aerogel-immobilized Chlorella vulgaris LH-1 on oil-contaminated seawater remediation and endogenous bacterial community diversity.

Ocean oil spills can severely impact ecosystems and disrupt marine biodiversity and habitats. Microbial remediation is an effective method for removing thin oil slick contamination. In this study, the adsorption and degradation of low-concentration oil spills by Chlorella vulgaris LH-1 immobilized in konjac glucomannan (KGM) aerogel were investigated. The effect of the KGM aerogel-immobilized C. vulgaris on the bacterial community structure in seawater environments was analyzed through bacterial diversity sequencing. In seawater containing 0.01 and 1.00 g/L of crude oil, after 14 days of remediation with the KGM aerogel-immobilized C. vulgaris, crude oil removal rates of 98.73% and 95.13% were achieved, respectively. The FDA hydrolytic enzyme activity curve indicated that the microbial growth activity in the immobilized C. vulgaris group was significantly higher than that in other groups. After remediation, the top three dominant bacterial genera in the seawater were found to be Vitellibacter, Roseitalea, and Methylophaga. Vitellibacter, a genus known for its ability to degrade polycyclic aromatic hydrocarbons (PAHs) in marine environments, showed increased abundance in seawater treated with the KGM aerogel-immobilized C. vulgaris, suggesting enhanced PAH degradation capability in the presence of the immobilized C. vulgaris. Functional prediction using PICRUSt indicated that the oil metabolism capability of bacteria was promoted by the KGM aerogel-immobilized C. vulgaris. PRACTITIONER POINTS: High degradation efficiency across various oil concentrations is exhibited by KGM-immobilized microalgae. KGM aerogels effectively confine C.vulgaris, reducing loss in marine systems. The impact of KGM aerogel-immobilized C. vulgaris on bacterial community structure in marine environments was analyzed. Immobilized C. vulgaris enhanced the growth of polycyclic aromatic hydrocarbon-degrading bacteria, such as Vitellibacter, in seawater.