Vibrio sp. dhg as a platform for the biorefinery of brown macroalgae

Beomhee Kim,Gyoo Yeol Jung,Sang Woo Seo,Chae Won Kang,Dong Hun Kwak,Sungwoo Park,Hyun Gyu Lim,Sunghwa Woo,Myung Hyun Noh,Jae-Seong Yang

doi:10.1038/s41467-019-10371-1

Beomhee Kim, Gyoo Yeol Jung + Show 8 more

Open Access

https://doi.org/10.1038/s41467-019-10371-1

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Abstract

Although brown macroalgae holds potential as an alternative feedstock, its utilization by conventional microbial platforms has been limited due to the inability to metabolize one of the principal sugars, alginate. Here, we isolate Vibrio sp. dhg, a fast-growing bacterium that can efficiently assimilate alginate. Based on systematic characterization of the genomic information of Vibrio sp. dhg, we establish a genetic toolbox for its engineering. We also demonstrate its ability to rapidly produce ethanol, 2,3-butanediol, and lycopene from brown macroalgae sugar mixture with high productivities and yields. Collectively, Vibrio sp. dhg can be used as a platform for the efficient conversion of brown macroalgae sugars into diverse value-added biochemicals.

Highlights

Brown macroalgae holds potential as an alternative feedstock, its utilization by conventional microbial platforms has been limited due to the inability to metabolize one of the principal sugars, alginate
While a conventional microbial platform (e.g., Escherichia coli) can metabolize mannitol, its ability to assimilate alginate is hindered by the fact that it lacks certain related genes; it is known that alginate metabolism requires about 10–20 genes that encode transporters, lyases, and metabolic enzymes[6,7]
For 2,3-BDO, it was similar to E. coli but more sensitive than C. glutamicum and S. cerevisiae; the growth was inhibited by 50 g L−1 of 2,3-BDO

Summary

Introduction

Brown macroalgae holds potential as an alternative feedstock, its utilization by conventional microbial platforms has been limited due to the inability to metabolize one of the principal sugars, alginate. Recent studies have demonstrated that E. coli can be engineered to utilize alginate with introduction a huge gene cluster for alginate utilization from naturally-occurring alginate-metabolizing microorganism[6,8], their growth rates and metabolic activities are still too low for industrial applications, likely due to the unoptimized expression of multiple xenogeneic genes As both the growth rate and the metabolic activity of host microorganisms greatly affect the performance of bioprocesses, it is crucial to exploit an efficient host with high rates of both these factors in order to obtain a high productivity. Due to natural optimization throughout evolutionary history, such microorganisms likely have a superior capacity to metabolize alginate compared with engineered versions of conventional microbes These naturally occurring microorganisms would be more suitable as a microbial platform for producing diverse value-added biochemicals from the sugars of brown macroalgae. By exploitation as a microbial platform, we demonstrate diverse value-added biochemical production from brown macroalgae sugars with high productivities and yields From these results, we propose Vibrio sp. We propose Vibrio sp. dhg as a platform for the biorefinery of brown macroalgae

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