Engineering aspects of microbial exopolysaccharide production

Freitas, Filomena; Torres, Cristiana A.V.; Reis, Maria A.M.

doi:10.1016/j.biortech.2017.05.092

Cited by 147 publications

(78 citation statements)

References 93 publications

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“…Considering that the antioxidant mechanisms of EPS are complex (Freitas, Torres, & Reis, ; Li et al, ), additional methods should be used in further investigations to re‐evaluate and compare the percentage of scavenging such as OH free radical, ABTS (Pan, Su, Cai, & Wei, ), and reducing powder. Simultaneously, studies on the chemical structure of EPS should be performed considering Fusarium oxysporum ( EBB‐ET‐01) as a potential candidate for the production of bioactive compounds.…”

Section: Resultsmentioning

confidence: 99%

Antioxidant activity of exo‐metabolites produced by Fusarium oxysporum: An endophytic fungus isolated from leaves of Otoba gracilipes

et al. 2019

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Tropical ecosystems hold an extremely diverse array of endophytic fungi, but their potential use still remains to be explored. In this study, we isolated an endophytic fungus from the leaves of Otoba gracilipes, a medicinal tree from a tropical rainforest in Colombia. Following isolation and cultivation, we evaluated its extracellular crude extract for antioxidant activity. Using traditional and molecular methods (ITS1, NL1 regions), the endophyte was identified as Fusarium oxysporum. Fresh spores from the fungal isolate were inoculated in liquid media (potato dextrose broth [PDB] and potato dextrose–yeast extract broth [PDYB]) and centrifuged for recovering extracellular polysaccharides from the exhausted medium after 30 days of cultivation. Crude extracts were recovered, purified, lyophilized, and evaluated for their ability to inactivate the free radical 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH). The extracts obtained from PDB culture media had a 51.5% of scavenging effect on DPPH after 5 min of reaction compared with the extracts from PDBY (26.4%), which suggests a high antioxidant potential of these fungal extracts. Thus, our results suggest other fungi from tropical ecosystems should be explored as potential sources of novel enzymes and other metabolites with bioactivity.

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Section: Resultsmentioning

confidence: 99%

Antioxidant activity of exo‐metabolites produced by Fusarium oxysporum: An endophytic fungus isolated from leaves of Otoba gracilipes

et al. 2019

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“…The advantage of scleroglucan is the possibility of having the product in a short time compared to the xanthan. Nevertheless, fungi like A. pullulans and S. rolfsii, the producers of pullulan and scleroglucan, respectively, can reach high productivity values (up to 18 and 13 g/L day, respectively [58]). Many works discuss properties of the xanthan-starch, and continues to develop these properties as additive for drilling muds.…”

Section: Discussionmentioning

confidence: 99%

Optimizing the transport of cuttings with ecological drilling muds: application to directional well

Hamed

2020

J Braz. Soc. Mech. Sci. Eng.

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This study is justified by the issues on site in directional well as blowouts, abnormal formation pressure, obstructions in the wellbore, inaccessible target locations caused by an obstacle (for example dome of salt) and the pollution of formations. The objective of this study is to optimize the hole cleaning in directional well with environmentally drilling muds. For this goal, different formulations of "green" drilling muds were tested for 4 inclinations of 10°, 20°, 30° and 40° compared with a horizontal plane for modeling the vertical drill. The drilling muds used are water based with environmentally friendly products; this study tested two biopolymer-based formulations, which are the constants of the experiment. For the specific needs of drilling muds, different products as clay, weighting and potassium chloride were added to the based solution. The microstructure and quantification of the chemical content of biopolymers were examined with SEM-EDS (scanning electronic microscope and energy dispersive X-ray spectrometer). Rheological properties were evaluated with modular rheometer; biopolymer solutions exhibit a non-Newtonian behavior. The samples tested in this study are compliant with API standards. For a suspension of macroscopic particles in the non-Newtonian environment, the sedimentation velocity shows a rapid increase according to the angle value which is well known in macroscopic suspensions under the name of "Boycott effect". The results showed the close link between the composition of the drilling mud and its ability to transport cuttings predictive for directional drilling.

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“…As representative biomacromolecules with low toxicity and good biocompatibility, microbial EPSs have attracted growing research interest, not only due to their unique rheological properties, but also because of their health‐related benefits and potential therapeutic uses (Freitas et al ). The water‐insoluble β‐1,3‐glucan curdlan is a rhizobial EPS produced by Agrobacterium and some Rhizobium strains that is well known for its immunostimulatory activities (Zhan et al ).…”

Section: Discussionmentioning

confidence: 99%

In vitroandin vivoanti‐inflammatory activity of a succinoglycan Riclin fromAgrobacteriumsp. ZCC3656

Cheng

Wang

et al. 2019

J Appl Microbiol

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Aims To purify and characterize an exopolysaccharide (EPS) from an Agrobacterium strain ZCC3656 with high EPS‐secreting performance and investigate its anti‐inflammatory activity using lipopolysaccharide (LPS)‐induced macrophage cells in an acute liver injury mouse model. Methods and Results Twelve rhizobial strains were compared for EPS fermentation production in modified M9 salts supplemented with mannitol or sucrose as the sole carbon source. Agrobacterium sp. ZCC3656 exhibited the highest EPS yield (21·1 g l−1) and was characterized for EPS production by carbon source utilization, time course fermentation and serial subcultivation assays. The EPS, designated Riclin, was purified by deproteinization using the Sevag method. The combined results of gel permeation chromatography, monosaccharide composition, methylation analysis and nuclear magnetic resonance analyses indicated that Riclin is a succinoglycan‐like polysaccharide comprised of glucose, galactose, succinate and pyruvate at a ratio of 7·8. : 1·0 : 0·9 : 1·1 and has an molecular weight of approximately 2·5 × 106 Da. Riclin inhibited TNF‐α, IL‐1β and IL‐6 expression in LPS‐stimulated RAW 264.7 macrophage cells in a dose‐dependent manner. In addition, Riclin pretreatment increased the survival rate of D‐Gal/LPS treated mice, inhibited serum ALT and AST activities and reduced the production of the inflammatory mediators TNF‐α, IL‐1β and IL‐6. Conclusions Agrobacterium sp. ZCC3656 is a highly stable EPS‐producing strain. The EPS Riclin from ZCC3656 is a succinoglycan‐type polysaccharide that is noncytotoxic and exhibits remarkable anti‐inflammatory effects in vivo and in vitro. Significance and Impact of the Study Succinoglycans are well known for good rheological properties and their physiological interactions with plants. However, their potential activity towards mammals has received little attention. Our study revealed that the succinoglycan Riclin exhibited excellent anti‐inflammatory activities and could be considered as a promising reagent in anti‐inflammatory treatment.

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Engineering aspects of microbial exopolysaccharide production

Cited by 147 publications

References 93 publications

Antioxidant activity of exo‐metabolites produced by Fusarium oxysporum: An endophytic fungus isolated from leaves of Otoba gracilipes

Antioxidant activity of exo‐metabolites produced by Fusarium oxysporum: An endophytic fungus isolated from leaves of Otoba gracilipes

Optimizing the transport of cuttings with ecological drilling muds: application to directional well

In vitroandin vivoanti‐inflammatory activity of a succinoglycan Riclin fromAgrobacteriumsp. ZCC3656

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