Enzymatic Transformations Involved in the Biosynthesis of Microbial Exo‐polysaccharides Based on the Assembly of Repeat Units

Schmid, Jochen; Sieber, Volker

doi:10.1002/cbic.201500035

Cited by 40 publications

(28 citation statements)

References 74 publications

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“…The biosynthetic pathways of sphingans are similar to those of group 1 and 4 capsule polysaccharides from E. coli 2324. The sanxan biosynthetic pathway also comprises a multi-step Wzx/Wzy-dependent process112324, which is divided into three sequential steps: (a) sugar-activated precursors are synthesized simultaneously; (b) tetrasaccharide repeat units are assembled into the inner membrane; and (c) the repeat units are polymerized and exported through the outer membrane.…”

Section: Resultsmentioning

confidence: 96%

“…The sanxan biosynthetic pathway also comprises a multi-step Wzx/Wzy-dependent process112324, which is divided into three sequential steps: (a) sugar-activated precursors are synthesized simultaneously; (b) tetrasaccharide repeat units are assembled into the inner membrane; and (c) the repeat units are polymerized and exported through the outer membrane. The detailed process and enzymes involved in sanxan synthesis are as follows.…”

Section: Resultsmentioning

confidence: 99%

“…S1). The tetrasaccharide repeat units were assembled on a lipid carrier comprising the C 55 -isoprenylphosphate carrier (IP), which was similar to the group I capsular polysaccharide in E. coli 2324.…”

Section: Resultsmentioning

confidence: 99%

“…The general scheme of sphingan biosynthesis follows the Wzx/Wzy-dependent pathway as described for Escherichia coli group I and IV polysaccharide2324. Biosynthetic pathways for sphingan S-8825, S-726, gellan1027, diutan28 and welan1129 have been identified.…”

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confidence: 99%

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The evolutionary life cycle of the polysaccharide biosynthetic gene cluster based on the Sphingomonadaceae

Huang

et al. 2017

Sci Rep

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Although clustering of genes from the same metabolic pathway is a widespread phenomenon, the evolution of the polysaccharide biosynthetic gene cluster remains poorly understood. To determine the evolution of this pathway, we identified a scattered production pathway of the polysaccharide sanxan by Sphingomonas sanxanigenens NX02, and compared the distribution of genes between sphingan-producing and other Sphingomonadaceae strains. This allowed us to determine how the scattered sanxan pathway developed, and how the polysaccharide gene cluster evolved. Our findings suggested that the evolution of microbial polysaccharide biosynthesis gene clusters is a lengthy cyclic process comprising cluster 1 → scatter → cluster 2. The sanxan biosynthetic pathway proved the existence of a dispersive process. We also report the complete genome sequence of NX02, in which we identified many unstable genetic elements and powerful secretion systems. Furthermore, nine enzymes for the formation of activated precursors, four glycosyltransferases, four acyltransferases, and four polymerization and export proteins were identified. These genes were scattered in the NX02 genome, and the positive regulator SpnA of sphingans synthesis could not regulate sanxan production. Finally, we concluded that the evolution of the sanxan pathway was independent. NX02 evolved naturally as a polysaccharide producing strain over a long-time evolution involving gene acquisitions and adaptive mutations.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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The evolutionary life cycle of the polysaccharide biosynthetic gene cluster based on the Sphingomonadaceae

Huang

et al. 2017

Sci Rep

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“…Extremophiles adapt to and tolerate harsh environmental conditions by synthesizing extracellular polysaccharides to withstand the external stress. Such microorganisms include Alcaligenes, Streptococcus, Halomonas, Pseudomonas and Shewanella [4].…”

Section: Introductionmentioning

confidence: 99%

Production of Microbial Exopolysaccharide by Cost-effective Medium Opimization Method

Nwosu

Abu

Agwa

2019

JAMB

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Microbial exopolysaccharide (EPS) emerged as a fast and high yielding sustainable polymeric substance which can be used as an alternative to synthetic polymer in industry. In this study, the influence of various nutritional and environmental factors of fermentation medium on bacterial growth and EPS production was evaluated by one factor at a time optimization. Efficient production medium was chosen from four different basal media and its carbon and nitrogen substrates were varied among organic and inorganic sources. Feasibility of bacterial utilization of some agricultural wastes as carbon and nitrogen sources to synthesize exopolysaccharide was compared. Carbon source of the fermentation medium was replaced with hydrolysates of sugarcane baggasse (SCB), sweet potato peels (SPP) or ripe plantain peels (RPP) at various concentrations while the nitrogen substrates was replaced with extracts of poultry droppings (PP), groundnut pod (GP) or beans bran (BB). Response results observed from single factor optimization were explored as center points to Nwosu et al.; JAMB, 19(2): 1-13, 2019; Article no.JAMB.52290 2 design a model for Response Surface Methodology study. Cell growth was determined from the biomass population of the fermentation broth after 5 days of incubation in a rotary shaker at 120 rpm at 30ºC. EPS was precipitated with pre-chilled ethanol (at 4ºC) from cell-free broth and overnight incubation at 4ºC. Total carbohydrate content was estimated by phenol-sulphuric acid method. Result obtained showed that 2% concentration Hydrolysate of SPP containing medium gave maximum yield of 2.26 g EPS/l of the medium as compared to sucrose containing medium with yield of 1.25 g EPS/l of the medium while highest production yield of 9.46 gEPS/l of the medium was obtained from 10 g/l BB extract medium as compared to yeast extract medium (5.41 gEPS/l). Results indicated that agricultural wastes such as sweet potato peel hydrolysate and bean bran extract could be developed as inexpensive alternative route to synthesize EPS from bacteria than inorganic substrates. Original Research Article

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Microbial Xanthan, Levan, Gellan, and Curdlan as Food Additives

Ateş

Öner

2017

Microbial Functional Foods and Nutraceuticals

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Enzymatic Transformations Involved in the Biosynthesis of Microbial Exo‐polysaccharides Based on the Assembly of Repeat Units

Cited by 40 publications

References 74 publications

The evolutionary life cycle of the polysaccharide biosynthetic gene cluster based on the Sphingomonadaceae

The evolutionary life cycle of the polysaccharide biosynthetic gene cluster based on the Sphingomonadaceae

Production of Microbial Exopolysaccharide by Cost-effective Medium Opimization Method

Microbial Xanthan, Levan, Gellan, and Curdlan as Food Additives

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