Use of extracellular polymeric substances as natural redox mediators to enhance denitrification performance by accelerating electron transfer and carbon source metabolism

The effect of carbon source, carbon to nitrogen (C/N) ratio, and limitation in nutrients (N, P, K, Ca, Mg, and Fe) on extracellular polymeric substances (EPS) synthesis by the marine bacteriumSaccharophagus degradanswas studied. This strain was able to grow in mineral medium and produce EPS with different efficiency according to the C source used (g EPS/L): glucose or starch (1.5 ± 0.2); galactose, sucrose, or xylose (0.7 ± 0.2); and fructose (0.3 ± 0.1). The C/N ratio (glucose/ammonium) had a significant effect on EPS biosynthesis due to its production rise as the C/N ratio increased from 3 to 100 (0.7 to 2.1 g EPS/L). It was also observed that limitation in nutrients such as N, P, K, Ca, Mg, and Fe also favored EPS biosynthesis. When taking into account both factors (C/N ratio, 100; nutrients limitation, 50%) a positive synergistic effect was noted on EPS production since under these conditions the maximum concentration obtained was 4.12 ± 0.3 g/L after 72 h of culture. The polymer was found to be a polysaccharide of mainly glucose, mannose, and galactose. This is the first report on EPS production byS. degradanswhich is a new feature of this versatile marine bacterium.

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Flocculation of Botryococcus Braunii with Glycine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1004-1005.877 ◽

2014 ◽

Vol 1004-1005 ◽

pp. 877-880 ◽

Cited By ~ 2

Author(s):

Xin Miao Xu ◽

Chao Zhou Chen ◽

Ying Shen

Keyword(s):

Carbon Source ◽

Extracellular Polymeric Substances ◽

Mixing Time ◽

Biomass Productivity ◽

Botryococcus Braunii ◽

Culture Period ◽

Solid Concentration ◽

Organic Carbon Source ◽

Biomass Recovery ◽

Low Levels

The objective of this paper was to optimize the flocculation and biomass productivity of Botryococcus braunii by using an organic carbon source glycine. The effects of culture period and glycine dose with high, medium and low levels on both solid concentration achieved and biomass productivity were conducted. It was found that extracellular polymeric substances (EPS), which promotes flocculation, was produced not only by bacterial but also by microalgae. The productivity of EPS was affected by culture period, glycine dose and mixing time. The maximum EPS of 103.3 mg/L obtained with 11 day culture period and 0.1 g/L glycine, leading to the maximum solid concentration achieved of 51 g/L, the biomass recovery rate 72%.

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Optimizing electron transfer from CdSe QDs to hydrogenase for photocatalytic H2 production

Chemical Communications ◽

10.1039/c9cc01150a ◽

2019 ◽

Vol 55 (39) ◽

pp. 5579-5582 ◽

Cited By ~ 16

Author(s):

Monica L. K. Sanchez ◽

Chang-Hao Wu ◽

Michael W. W. Adams ◽

R. Brian Dyer

Keyword(s):

Quantum Dots ◽

Electron Transfer ◽

Reduction Potential ◽

H2 Production ◽

Cdse Quantum Dots ◽

Redox Mediators ◽

Cdse Qds ◽

Electron Shuttles ◽

Hydrogenase Enzyme

A series of viologen related redox mediators of varying reduction potential has been characterized and their utility as electron shuttles between CdSe quantum dots and hydrogenase enzyme has been demonstrated.

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