Toward Understanding the Alginate Catabolism in Microbulbifer sp. ALW1 by Proteomics Profiling

Zhipeng Li; Xiaoyi Huang; Yuxi Guo; Chenghao Zhang; Liang Yang; Xiping Du; Hui Ni; Xuchu Wang; Yanbing Zhu

doi:10.3389/fbioe.2022.829428

Toward Understanding the Alginate Catabolism in Microbulbifer sp. ALW1 by Proteomics Profiling

Front Bioeng Biotechnol. 2022 Mar 16:10:829428. doi: 10.3389/fbioe.2022.829428. eCollection 2022.

Authors

Zhipeng Li^{1

2

3}, Xiaoyi Huang¹, Yuxi Guo¹, Chenghao Zhang¹, Liang Yang¹, Xiping Du^{1

2

3}, Hui Ni^{1

2

3}, Xuchu Wang⁴, Yanbing Zhu^{1

2

3}

Affiliations

¹ College of Ocean Food and Biology Engineering, Jimei University, Xiame, China.
² Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering Technology, Xiamen, China.
³ Research Center of Food Biotechnology of Xiamen City, Xiamen, China.
⁴ Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Ministry of Education, Hainan Normal University, Haikou, China.

Abstract

The bacterial strain of Microbulbifer sp. ALW1 has demonstrated visible ability of degrading the cell wall of Laminaria japonica, and biochemical characterization has been performed on some individual enzymes to elucidate its genetic basis. However, it still remains elusive how strain ALW1 successfully breaks down the major cell wall component alginate polysaccharide and colonizes on its marine host. In this study, a mass spectrometry-based quantitative analysis of the extracellular and intracellular proteomes was introduced to elucidate the alginate degradation pathway in ALW1 strain. Mass spectrometry and biochemical assays indicated that strain ALW1 could effectively degrade alginate polysaccharide into disaccharides and trisaccharides within 12 h. Proteome analysis identified 156 and 1,047 proteins exclusively localized in extracellular and intracellular compartments, respectively, with 1,086 protein identities of dual localization. Functional annotation of the identified proteins suggested the involvement of diverse catalytic enzymes and non-catalytic molecules for the cleavage and metabolism of alginate polysaccharide. A simplified pathway was constructed to demonstrate the extracellular digestion, active transport, and intracellular conversion of alginate polysaccharide and its fragmented oligosaccharides, casting a picture of genetic loci controlling alginate catabolism by ALW1 strain. This study aims to provide a guide for utilization and genetic manipulation of the bacterial strain ALW1 for efficient alginate oligosaccharides production by fermentation.

Keywords: Microbulbifer sp. ALW1; alginate catabolism; oligosaccharides; polysaccharides; proteomics.