Page 140 - 《水产学报》2026年第3期

3 期 水 产 学 报 50 卷

Extraction of colanic acid of marine bacteria and its effects on
the settlement of Mytilus coruscus plantigrades

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WU Yefan , XIE Jingyi , PENG Lihua 1,2,3 , YANG Jinlong 1,2,3 , LIANG Xiao 1,2,3*
(1. College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China;
2. International Research Center for Marine Biosciences, Ministry of Science and Technology,
Shanghai Ocean University, Shanghai 201306, China;
3. Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture animals,
Shanghai Ocean University, Shanghai 201306, China)

Abstract: To investigate the mechanism by which the exopolysaccharide colanic acid (CA) from marine bacteria induces the
attachment of Mytilus coruscus, juvenile M. coruscus were used as experimental subjects. The optimal culture conditions for
CA production were explored, followed by extraction, purification, and monosaccharide composition analysis of CA. Different
concentrations of CA were applied to induce mussel settlement, and quantitative real-time polymerase chain reaction (qRT-
PCR) was performed after CA injection to evaluate the byssus attachment efficiency. In this study, a genetically engineered
strain of Pseudoalteromonas marina ECSMB14103 Δ01912 with high CA production was used. Through single-factor experi-
ments and Box-Benhnken central composite design optimization of extraction culture conditions, the optimal cultivation
scheme for CA production in this strain was determined. The optimal scheme for CA production is a pH of 6.0, cultivation tem-
perature of 30 ℃, cultivation time of 18 h, and inoculum of 8%. Ion chromatography analysis revealed that the product con-
sisted of a heteropolysaccharide composed of fucosylglucose, mannose, glucose, and glucuronic acid in a molar ratio of
2∶2∶1∶1. CA concentrations of 20 μg/mL and 50 μg/mL embedded on glass slides, resulted in the highest inducing activity
of M. coruscus plantigrades. Injection of purified CA into mussels showed significant up-regulation of the expression levels of
Mcfp-1P, Mcfp-2 and Mcfp-5 genes, which encode adhesive proteins in byssal threads. No significant changes were observed in
the expression levels of the Mcfp-1T gene after treatment with CA. Furthermore, the expression level of the Mccol2 gene signi-
ficantly increased, while Mccol3 expression significantly decreased. These findings suggest that CA may regulate the settle-
ment of M. coruscus plantigrades through promoting secretion of adhesive proteins from byssal threads, and modulating differ-
ent types of collagen proteins. This study provides a theoretical basis for exploring the mechanism of inducing the settlement of
M. coruscus and has potential value in applying CA-induced settlement to the aquaculture of M. coruscus.
Key words: Mytilus coruscus; colanic acid; extraction optimization; settlement; byssus proteins
Corresponding author: LIANG Xiao. E-mail: x-liang@shou.edu.cn

Funding projects: National Key Research and Development Program of China (2023YFD2401902, 2023YFE0115500);
National Natural Science Foundation of China (41876159)

https://www.china-fishery.cn 中国水产学会主办 sponsored by China Society of Fisheries
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