Extracellular Enzyme Activity and Its Implications for Organic Matter Cycling in Northern Chinese Marginal Seas

Li, Yang; Sun, Liangdan; Sun, Yuanyuan; Cha, Qian‐Qian; Li, Chunyang; Zhao, Dian‐Li; Song, Xin; Wang, Min; McMinn, Andrew; Chen, Xiu-Lan; Zhang, Yuzhong; Qin, Qi‐Long

doi:10.3389/fmicb.2019.02137

Cited by 24 publications

(13 citation statements)

References 72 publications

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“…Five extracellular enzymes including protease, lipase, urease, α-glucosidase, and phosphatase were produced by A. limacinum BUCHAXM 122, consistent with previous reports for other species of Aurantiochytrium [23,34] and also for Shizochytrium and Thraustochytrium [34]. Similar to the ecosystem in which A. limacinum is found, phosphatase, βglucosidase and protease are also found in the bacteria such as Planctomycetes, Chloroflexi, Roseobacter, Alteromonas and Pseudoalteromonas [35]. However, most bacteria that live in seawater, sediment, plants and animals produce lipase phosphatase and protease, and a few produce urease [36].…”

Section: Discussionsupporting

confidence: 87%

Characterization and PUFA production of Aurantiochytrium limacinum BUCHAXM 122 isolated from fallen mangrove leaves

Sirirak¹,

Suanjit²,

Powtongsook³

et al. 2020

ScienceAsia

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Aurantiochytrium limacinum BUCHAXM 122, a strain of thraustochytrid microorganism is potentially an alternative source of essential nutrients for commercial products. In this study, the strain was screened for its characterization and determination of polyunsaturated fatty acid (PUFA) production. Cells were isolated from fallen mangrove leaves, and grown in a glucose-yeast extract-peptone (GYP) medium. Their morphology, life cycle, biomass, fatty acid, extracellular enzymes and major elements were also investigated. Colonies occurred prominently on the fourth day of cultivation, appearing opaque white in color and containing large numbers of amoeboid cells. These thraustochytrids were observed to have a multi-stage life cycle, developing through zoospore, vegetative and zoosporangium stages with a life span of approximately 24 h. Zoospores developed into vegetative cells within 10-12 h and vegetative cells developed into zoosporangia, releasing zoospores, within approximately 10-15 h. Results showed that A. limacinum BUCHAXM 122 produced highest biomass at 108 h, with 23.85 ± 1.02 g/l dry weight. The isolates had high content of docosahexaenoic acid (DHA; 30.31 ± 5.88% of total fatty acids), indicating that they could serve as a fatty acid source for human consumption and aquaculture feeds. Major elemental analysis showed that cells contained 57% carbon, 29% oxygen, 9% hydrogen, 4% nitrogen and 1% sulfur. Extracellular degradative enzymes including protease, lipase, urease, α-glucosidase and phosphatase activities were also detected.

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Section: Discussionsupporting

confidence: 87%

Characterization and PUFA production of Aurantiochytrium limacinum BUCHAXM 122 isolated from fallen mangrove leaves

Sirirak¹,

Suanjit²,

Powtongsook³

et al. 2020

ScienceAsia

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“…These results point to possible contributions of microbial metabolites such as organic acids or extracellular enzymes to MAOM mobilization. Both have recently been implicated in the release of MAOM, either through the displacement of weakly bound compounds or enzymatic hydrolysis of surface-bound polymers. , A recent study showed that ectomycorrhizal fungi growing in media facilitated the mobilization of polymeric MAOM from goethite. MAOM mobilization was attributed to the interplay of fungal metabolites coating the surfaces and extracellular enzymes depolymerizing complex MAOM, bypassing the desorption step .…”

Section: Discussionmentioning

confidence: 99%

Simple Plant and Microbial Exudates Destabilize Mineral-Associated Organic Matter via Multiple Pathways

Bölscher

Winnick

et al. 2021

Environ. Sci. Technol.

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Most mineral-associated organic matter (MAOM) is protected against microbial attack, thereby contributing to long-term carbon storage in soils. However, the extent to which reactive compounds released by plants and microbes may destabilize MAOM and so enhance microbial access, as well as the underlying mechanisms, remain unclear. Here, we tested the ability of functionally distinct model exudatesligands, reductants, and simple sugarsto promote microbial utilization of monomeric MAOM, bound via outer-sphere complexes to common iron and aluminum (hydr)oxide minerals. The strong ligand oxalic acid induced rapid MAOM mineralization, coinciding with greater sorption to and dissolution of minerals, suggestive of direct MAOM mobilization mechanisms. In contrast, the simple sugar glucose caused slower MAOM mineralization, but stimulated microbial activity and metabolite production, indicating an indirect microbially-mediated mechanism. Catechol, acting as reductant, promoted both mechanisms. While MAOM on ferrihydrite showed the greatest vulnerability to both direct and indirect mechanisms, MAOM on other (hydr)oxides was more susceptible to direct mechanisms. These findings suggest that MAOM persistence, and thus long-term carbon storage within a given soil, is not just a function of mineral reactivity but also depends on the capacity of plant roots and associated microbes to produce reactive compounds capable of triggering specific destabilization mechanisms.

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“…At all sites, similar proportions of taxa were recorded. At the phylum level they were represented by Bacterioidetes, Proteobacteria and Actinobacteria (Figure 5), which have the ability to produce a variety of extracellular enzymes and have been identified as dominant bacterial taxa in both marine [57] and riverine [30] environments. With more than 18% share in the total microbial community in the middle river course, Flavobacterium dominated at the genus level (Figure 6).…”

Section: Discussionmentioning

confidence: 99%

Patterns of Structural and Functional Bacterioplankton Metacommunity along a River under Anthropogenic Pressure

Małecka-Adamowicz

Kubera

2021

Sustainability

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Bacteria, an integral part of aquatic ecosystems, are responsible for the circulation of matter and flow of energy. Since bacterioplankton rapidly responds to any natural and human-induced disturbances in the environment, it can serve as a bioindicator of these changes. Knowing factors that shape the microbial community structure may help the sustainable management of the water environment. However, the identification of environmental signals affecting the structure and function of bacterioplankton is still a challenge. The study analyses the impact of environmental variables on basic microbial parameters, which determines the effectiveness of ecological processes in rivers. Measurements of bacterioplankton abundance (BA) and extracellular enzyme activity (EEA) were based on fluorescent markers. The bacterial community structure was determined by 16S rRNA gene amplicon sequencing (Illumina). The results indicate spatial variation in bacterioplankton abundance. Temporal variation was not significant. Lipase and aminopeptidase had the highest level of activity. EEA was not correlated with bacterial abundance but was significantly correlated with temperature. Moreover, differences in lipase, α-glucosidase and β-glucosidase activity levels between spring and summer were noted. At the same time, the location of sampling site had a significant influence on aminopeptidase activity. The taxonomic analysis of bacterioplankton communities in the Brda River indicated that, although different numbers of OTUs were recorded in the studied river sections, bacterioplankton biodiversity did not change significantly along the river with distance downstream. Anthropogenically modified river sections were characterized by the dominance of Flavobacterium (Bacterioidetes) and hgcl clade (Actinobacteria) taxa, known for their ability to produce extracellular enzymes. PCoA analysis revealed that the sites located in the lower river course (urban area) had the most similar bacterial community structure (β-diversity). The study provides new insight into the changes in microbial communities along the river and emphasizes the potential impact of anthropogenization on these processes.

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Extracellular Enzyme Activity and Its Implications for Organic Matter Cycling in Northern Chinese Marginal Seas

Cited by 24 publications

References 72 publications

Characterization and PUFA production of Aurantiochytrium limacinum BUCHAXM 122 isolated from fallen mangrove leaves

Characterization and PUFA production of Aurantiochytrium limacinum BUCHAXM 122 isolated from fallen mangrove leaves

Simple Plant and Microbial Exudates Destabilize Mineral-Associated Organic Matter via Multiple Pathways

Patterns of Structural and Functional Bacterioplankton Metacommunity along a River under Anthropogenic Pressure

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