Anaerobic Production of Extracellular Polysaccharide by Butyrivibrio fibrisolvens nyx

Abstract

Anaerobic production of extracellular polysaccharide (EP) was examined, using a previously uncharacterized, obligately anaerobic rumen isolate, Butyrivibrio fibrisolvens nyx, which produced an EP that was rheologically similar to xanthan gum. The main objectives were to determine the nutritional requirements and conditions which promoted EP production by strain nyx. Strain nyx was grown anaerobically in defined and semidefined media. In addition to carbohydrate and nitrogen sources, strain nyx required acetic acid, folic acid, biotin, and pyridoxamine. Strain nyx produced similar amounts of EP at 35 to 40°C. Conditions that improved growth usually improved EP production. Of the carbohydrates tested, glucose supported the fastest growth and most EP production, followed by sucrose, xylose, and lactose. Strain nyx utilized ammonium sulfate, urea, or vitamin-free casein hydrolysate as nitrogen sources for growth and EP production. At 2 and 20 g/liter, respectively, ammonium sulfate and vitamin-free casein hydrolysate supported about the same rates of growth and EP production. EP was not produced in the lag or stationary phases, and EP production was exponential during exponential cell growth. Based on the results of this work, anaerobic EP production with B. fibrisolvens nyx could reduce energy costs for industrial EP production compared with the cost of aerated systems. Finally, this work demonstrated that, under appropriate growth conditions, a gastrointestinal tract (ruminal) microorganism produced high levels of EP.

Biological responses to P‐limitation in indigenous bacteria isolated from drinking water

“…It is reported that the initial concentration of available carbon and nitrogen is crucial for EPS production rather than the absolute ratio (Bonet et al, 1993). Similar effects have been reported for Zoogloea strain MP6 (gram‐negative, betaproteobacteria) (Unz & Farrah, 1976) and Butyrivibrio fibriosolvens (gram‐positive, clostridia) (Wachenheim & Patterson, 1992) for exopolysaccharides production.…”

Some chemical and physical properties of extracellular polysaccharides produced by Butyrivibrio fibrisolvens strains

“…While not examined in this study, the manipulation of cultural conditions may lead to enhancement of EP production. A previous study with B. fibrisolvens NYX has shown that EP production can be influenced by the nitrogen sources used for growth (26). The ability to grow most B. fibrisolvens strains on defined media suggests that further nutritional manipulations are possible.…”

Effects of zinc-treated soybean meal on ruminal fermentation and intestinal amino acid flows in steers fed corn silage-based diets2

“…Ten milliliters of fluid was acidified with 1 mL of 6 N HCl and frozen; samples later were thawed and centrifuged at 25,000 x g for 20 min. The supernatant was analyzed for NH3N (Chaney and Marbach, 1962) and VFA (Wachenheim and Patterson, 1992).…”