Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4

Phycosphere niches host rich, unique microbial consortia that harbor complex algae–bacteria interactions with fundamental significance in underpinning most functions of aquatic ecological processes. Therefore, harvesting the uncultured phycobacteria is crucial for understanding the intricate mechani...

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Main Authors: Xiaoling Zhang, Zekang Pan, Jinkai Zhang, Bingqian Liu, Qiao Yang
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/6/1198
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author Xiaoling Zhang
Zekang Pan
Jinkai Zhang
Bingqian Liu
Qiao Yang
author_facet Xiaoling Zhang
Zekang Pan
Jinkai Zhang
Bingqian Liu
Qiao Yang
author_sort Xiaoling Zhang
collection DOAJ
description Phycosphere niches host rich, unique microbial consortia that harbor complex algae–bacteria interactions with fundamental significance in underpinning most functions of aquatic ecological processes. Therefore, harvesting the uncultured phycobacteria is crucial for understanding the intricate mechanisms governing these dynamic interactions. Here, we characterized and compared microbial community composition of the phycosphere microbiota from six harmful algal bloom-forming marine dinoflagellates, <i>Alexandrium</i> spp., and their bacterial associations. Furthermore, based on a combinational enhanced cultivation strategy (CECS) procedure for the selected isolation for cultivable phycobacteria, a new yellow-pigmented bioactive bacterium designated ABI-6-9 was successfully recovered from cultivable phycobacteria of the highly toxic <i>A. minutum</i> strain amtk4. An additional phylogenomic analysis fully identified this new isolate as a potential novel species of the genus <i>Mameliella</i> within the family <i>Roseobacteraceae</i>. The bioactivity evaluation observed that strain ABI-6-9 can significantly promote the cell growth of its algal host and altered the gonyautoxin accumulation profiles in the co-culture circumstance. Additionally, the bacterial production of active bioflocculanting exopolysaccharides (EPSs) by strain ABI-6-9 was also measured after culture optimization. Thus, these findings revealed the potential environmental and biotechnological implications of this new microalgae growth- promoting phycobacterium.
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spelling doaj-art-7609b219512e47e4a22044abd0943ac02025-08-20T02:21:04ZengMDPI AGMicroorganisms2076-26072025-05-01136119810.3390/microorganisms13061198Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4Xiaoling Zhang0Zekang Pan1Jinkai Zhang2Bingqian Liu3Qiao Yang4ABI Group, Phycosphere Microbiology Laboratory, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan 316022, ChinaABI Group, Phycosphere Microbiology Laboratory, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan 316022, ChinaABI Group, Phycosphere Microbiology Laboratory, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan 316022, ChinaABI Group, Phycosphere Microbiology Laboratory, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan 316022, ChinaABI Group, Phycosphere Microbiology Laboratory, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan 316022, ChinaPhycosphere niches host rich, unique microbial consortia that harbor complex algae–bacteria interactions with fundamental significance in underpinning most functions of aquatic ecological processes. Therefore, harvesting the uncultured phycobacteria is crucial for understanding the intricate mechanisms governing these dynamic interactions. Here, we characterized and compared microbial community composition of the phycosphere microbiota from six harmful algal bloom-forming marine dinoflagellates, <i>Alexandrium</i> spp., and their bacterial associations. Furthermore, based on a combinational enhanced cultivation strategy (CECS) procedure for the selected isolation for cultivable phycobacteria, a new yellow-pigmented bioactive bacterium designated ABI-6-9 was successfully recovered from cultivable phycobacteria of the highly toxic <i>A. minutum</i> strain amtk4. An additional phylogenomic analysis fully identified this new isolate as a potential novel species of the genus <i>Mameliella</i> within the family <i>Roseobacteraceae</i>. The bioactivity evaluation observed that strain ABI-6-9 can significantly promote the cell growth of its algal host and altered the gonyautoxin accumulation profiles in the co-culture circumstance. Additionally, the bacterial production of active bioflocculanting exopolysaccharides (EPSs) by strain ABI-6-9 was also measured after culture optimization. Thus, these findings revealed the potential environmental and biotechnological implications of this new microalgae growth- promoting phycobacterium.https://www.mdpi.com/2076-2607/13/6/1198phycosphere microbiologyalgae–bacteria interactionsexopolysaccharidescultivable phycobacteriamicroalgae growth-promoting bacteriumtoxic dinoflagellate
spellingShingle Xiaoling Zhang
Zekang Pan
Jinkai Zhang
Bingqian Liu
Qiao Yang
Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4
Microorganisms
phycosphere microbiology
algae–bacteria interactions
exopolysaccharides
cultivable phycobacteria
microalgae growth-promoting bacterium
toxic dinoflagellate
title Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4
title_full Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4
title_fullStr Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4
title_full_unstemmed Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4
title_short Phycobacteria Biodiversity, Selected Isolation, and Bioactivity Elucidation of New Bacterial Species of Highly Toxic Marine Dinoflagellate <i>Alexandrium minutum</i> amtk4
title_sort phycobacteria biodiversity selected isolation and bioactivity elucidation of new bacterial species of highly toxic marine dinoflagellate i alexandrium minutum i amtk4
topic phycosphere microbiology
algae–bacteria interactions
exopolysaccharides
cultivable phycobacteria
microalgae growth-promoting bacterium
toxic dinoflagellate
url https://www.mdpi.com/2076-2607/13/6/1198
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