Dataset Information

Denitrification performance of Pseudomonas fluorescens Z03 immobilized by graphene oxide-modified polyvinyl-alcohol and sodium alginate gel beads at low temperature.

ABSTRACT: Improving the effect of microbial denitrification under low-temperature conditions has been a popular focus of research in recent years. In this study, graphene oxide (GO)-modified polyvinyl-alcohol (PVA) and sodium alginate (SA) (GO/PVA-SA) gel beads were used as a heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria (Pseudomonas fluorescens Z03) carrier to enhance nitrogen removal efficiency levels at low temperatures (6-8°C). The removal efficiency of NH4??+-N and NO3???--N and the variations in concentrations of extracellular polymeric substances (EPS) under different GO doses (0.03-0.15 g l-1) were studied. The results indicated that the addition of GO can improve the efficiency of nitrogen removal, and the highest removal efficiency level and highest carbohydrate, protein, and total EPS content levels (50.28 mg, 132.78 mg and 183.06 mg (g GO/PVA-SA gel)-1, respectively) were obtained with 0.15 g l-1 GO. The simplified Monod model accurately predicted the nitrogen removal efficiency level. These findings suggested that the application of GO serves as an effective means to enhance nitrogen removal by stimulating the activity of HN-AD bacteria.

SUBMITTER: Tang M

PROVIDER: S-EPMC7137976 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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Denitrification performance of <i>Pseudomonas fluorescens</i> Z03 immobilized by graphene oxide-modified polyvinyl-alcohol and sodium alginate gel beads at low temperature.

Tang Meizhen M Jiang Jie J Lv Qilin Q Yang Bin B Zheng Mingna M Gao Xin X Han Jindi J Zhang Yingjie Y Yang Yuewei Y

Royal Society open science 20200304 3

Improving the effect of microbial denitrification under low-temperature conditions has been a popular focus of research in recent years. In this study, graphene oxide (GO)-modified polyvinyl-alcohol (PVA) and sodium alginate (SA) (GO/PVA-SA) gel beads were used as a heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria (<i>Pseudomonas fluorescens</i> Z03) carrier to enhance nitrogen removal efficiency levels at low temperatures (6-8°C). The removal efficiency of NH4 +-N and NO3 ...[more]

PMID: 32269792

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Project description:The lipase from Pseudomonas fluorescens (PFL) has been immobilized on octyl-agarose beads under 16 different conditions (varying pH, ionic strength, buffer, adding some additives) at two different loadings, 1 and 60 mg of enzyme/g of support with the objective of check if this can alter the biocatalyst features. The activity of the biocatalysts versus p-nitrophenyl butyrate and triacetin and their thermal stability were studied. The different immobilization conditions produced biocatalysts with very different features. Considering the extreme cases, using 1 mg/g preparations, PFL stability changed more than fourfolds, while their activities versus pNPB or triacetin varied a 50-60%. Curiously, PFL specific activity versus triacetin was higher using highly enzyme loaded biocatalysts than using lowly loaded biocatalysts (even by a twofold factor). Moreover, stability of the highly loaded preparations was higher than that of the lowly loaded preparations, in many instances even when using 5°C higher temperatures (e.g., immobilized in the presence of calcium, the highly loaded biocatalysts maintained after 24 h at 75°c a 85% of the initial activity, while the lowly loaded preparation maintained only 27% at 70°C). Using the highly loaded preparations, activity of the different biocatalysts versus pNPB varied almost 1.7-folds and versus triacetin 1.9-folds. In this instance, the changes in stability caused by the immobilization conditions were much more significant, some preparations were almost fully inactivated under conditions where the most stable one maintained more than 80% of the initial activity. Results suggested that immobilization conditions greatly affected the properties of the immobilized PFL, partially by individual molecule different conformation (observed using lowly loaded preparations) but much more relevantly using highly loaded preparations, very likely by altering some enzyme-enzyme intermolecular interactions. There is not an optimal biocatalyst considering all parameters. That way, preparation of biocatalysts using this support may be a powerful tool to tune enzyme features, if carefully controlled.

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Dataset Information

Denitrification performance of Pseudomonas fluorescens Z03 immobilized by graphene oxide-modified polyvinyl-alcohol and sodium alginate gel beads at low temperature.

Publications

Denitrification performance of <i>Pseudomonas fluorescens</i> Z03 immobilized by graphene oxide-modified polyvinyl-alcohol and sodium alginate gel beads at low temperature.

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