Screening of local wild-type Xanthomonas spp. for xanthan biosynthesis using media with different carbon sources

Abstract

In this study the screening of different Xanthomonas strains, isolated from infected crucifers and pepper leaves, for xanthan biosynthesis on semi-synthetic media containing different carbon sources was performed. The success of xanthan biosynthesis was estimated based on xanthan concentration in media and its molecular weight. Glucose and glycerol were investigated as carbon sources in a quantity of 20.0 g/L. Xanthan biosynthesis by different Xanthomonas isolates on two different cultivation media was carried out in Erlenmeyer flasks under aerobic conditions for 168 h. According to the obtained results selection of the carbon source, producing strain and their combination have a statistically significant effect on xanthan quantity and quality. The results obtained in this study indicate that local wild-type Xanthomonas strains isolated from pepper leaves have a great potential for application in biotechnological production of good-quality xanthan on glycerol-based media.

Screening of Local Wild Xanthomonas Species for Xanthan Production on Crude Glycerol-based Medium

“…According to the results shown in Fig. 3 (a), values of average molecular weight of xanthan were in range from 0.5 × 10 5 g/moL to 2.3 × 10 5 g/moL and are in agreement with results from previous research (1.0 × 10 5 g/moL to 6.0 × 10 5 g/moL) when Xanthomonas strains isolated from crucifers were cultivated on media with different carbon sources, including glycerol [26].…”

“…The values of average molecular weight of xanthan obtained in this study were in range from around 0.5 × 10 5 g/moL to 2.8 × 10 5 g/moL. The obtained results are in accordance with the results from previous research where X. euvesicatoria strains isolated from pepper leaves were cultivated on media with different carbon sources, including glycerol, and average molecular weight of produced xanthan was in range from 1.0 × 10 5 g/moL to 8.0 × 10 5 g/moL [26].…”

“…On the other side, there is also no statistically significant difference in the values of xanthan concentration in media when strains PL1, PL2, PL3 and PL5 were used. The obtained results of xanthan concentration in media varied from around 5.00 g/L to 8.00 g/L and are in agreement with results obtained in the previous study where xanthan production was performed on glycerol-based medium by the same strains, and the xanthan yield was in range from around 5.00 g/L to 10 g/L [26].…”

“…Bacteria of the species X. campestris and X. euvesicatoria are catalase positive and oxidase negative and have the ability to produce acid from glucose, arabinose, galactose, dextrin, mannose etc. [20,26]. About 90% of glucose is primarily catabolized via the Entner-Doudoroff pathway in Xanthomonas sp.…”

“…Strains of X. campestris were found causing disease on crucifers while X. euvesicatoria strains essentially infects peppers [20,27]. Results from recent study suggest that Xanthomonas strains isolated from crucifers have the ability to metabolize glucose in higher degree than glycerol, while Xanthomonas strains isolated from pepper leaves metabolize glycerol in higher degree than glucose [26].…”