PRODUCTION OF EXOPOLYSACCHARIDES BY Halomonas eurihalina F2-7 AND Xanthomonas campestris pv. Campestris FROM SALTED WHEY | ||||
| Journal of Food and Dairy Sciences | ||||
| Article 5, Volume 32, Issue 2, February 2007, Page 1203-1216 PDF (566.9 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jfds.2007.198700 | ||||
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| Authors | ||||
| A. A. Ali; M. A. A. Azzam; A. M. Metwally; A. A. Awad | ||||
| Dairy Dept., Fac. Of Agric. Cairo Univ. | ||||
| Abstract | ||||
| Salted whey produced from the Egyptian Domiati cheese (soft chees) after supplementing with carbon and nitrogen sources was used for production of exopolysaccharide (EPS) by Halomonas eurihalina F2-7 and Xanthomonas campestris pv. campestris. The effect of whey pH, salt percent, sugars and non-protein nitrogen contents and the microorganism inoculum size and fermentation temperature and period on microorganism growth and EPS yield and their dry mutter and sugars content were studied. Fermentation medium components which produces maximum cells growth and EPS yield varied between both microorganisms. H. eurihalina F2-7 (3.0% inoculum) produced maximum EPS yield (2.8 g/L) when the whey contained 7.0% salt, supplemented with mannitol (10 g/L) and yeast extract (6 g/L) and the pH was 7.2 at 32°C for 10 days. While X. campestris pv. campestris (3.%inoculum) resulted in 13.6 g/L EPS (~ 5 times of Halomonas EPS) when grown in whey which its protein was hydrolyzed (≥67.15% hydrolysis ratio), salted with 3.0% NaCl, and supplemented with 3.0% sucrose at pH 7.5 for 5 days under shaking (200 rpm/min) at 25°C. Sugars content of the EPS was also affected by the growth medium and the produced organism. Glucose and mannose appeared to be the principal sugars but with varying ratios. The EPS yield followed the trend of its cells growth and the yield reached the maximum at the microorganism stationary phase. Both microorganisms differed in their EPS yield and their effect on fermentation pH. While H. eurihalina F2-7 increased the pH from 7.2 to 7.95, X. campestris pv. campestris reduced the pH from 7.5 to 6.65. | ||||
| Keywords | ||||
| Exopolysaccharides (EPS); H. eurihalina F2-7; X. campestris pv. campestris; Salted whey; Carbon & Nitrogen sources; Fermentation conditions; EPS yield and composition | ||||
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