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Direct bio-utilization of untreated rapeseed meal for effective iturin A production by Bacillus subtilis in submerged fermentation.

Jin H, Zhang X, Li K, Niu Y, Guo M, Hu C, Wan X, Gong Y, Huang F - PLoS ONE (2014)

Bottom Line: A significant promoting effect of rapeseed meal on iturin A production was observed and the maximum iturin A concentration of 0.60 g/L was reached at 70 h, which was 20% and 8.0 fold higher than that produced from peptone and ammonium nitrate media, respectively.Moreover, compared to raw rapeseed meal, the remaining residue following fermentation could be used as a more suitable supplementary protein source for animal feed because of the great decrease of major anti-nutritional components including sinapine, glucosinolate and its degradation products of isothiocyanate and oxazolidine thione.The results obtained from this study demonstrate the potential of direct utilization of low cost rapeseed meal as a nitrogen source for commercial production of iturin A and other secondary metabolites by Bacillus subtilis.

View Article: PubMed Central - PubMed

Affiliation: Oil Crops Research Institute, Chinese Academy of Agriculture Sciences, Wuhan, China; Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, China.

ABSTRACT
The feasibility of using untreated rapeseed meal as a nitrogen source for iturin A production by Bacillus subtilis 3-10 in submerged fermentation was first evaluated by comparison with two different commercial nitrogen sources of peptone and ammonium nitrate. A significant promoting effect of rapeseed meal on iturin A production was observed and the maximum iturin A concentration of 0.60 g/L was reached at 70 h, which was 20% and 8.0 fold higher than that produced from peptone and ammonium nitrate media, respectively. It was shown that rapeseed meal had a positive induction effect on protease secretion, contributing to the release of soluble protein from low water solubility solid rapeseed meal for an effective supply of available nitrogen during fermentation. Moreover, compared to raw rapeseed meal, the remaining residue following fermentation could be used as a more suitable supplementary protein source for animal feed because of the great decrease of major anti-nutritional components including sinapine, glucosinolate and its degradation products of isothiocyanate and oxazolidine thione. The results obtained from this study demonstrate the potential of direct utilization of low cost rapeseed meal as a nitrogen source for commercial production of iturin A and other secondary metabolites by Bacillus subtilis.

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Time courses of the number of viable cells (A), iturin A concentration (B), reducing sugar (C) and soluble protein concentration (D) with different nitrogen sources in bioreactor batch fermentation.•: rapeseed meal; ▪: peptone; ▴: ammonium nitrate. Error bars represent the standard deviation of the means (N = 3).
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pone-0111171-g003: Time courses of the number of viable cells (A), iturin A concentration (B), reducing sugar (C) and soluble protein concentration (D) with different nitrogen sources in bioreactor batch fermentation.•: rapeseed meal; ▪: peptone; ▴: ammonium nitrate. Error bars represent the standard deviation of the means (N = 3).

Mentions: To further investigate the application potential of low-cost rapeseed meal as nitrogen source on iturin A production, two different commercial nitrogen sources, peptone and ammonium nitrate, were applied in batch fermentations to compare the production performance of iturin A with that produced from rapeseed meal in a 7-L bioreactor. The optimal concentrations of peptone and ammonium nitrate were finalized at 30 and 8 g/L, respectively, based on our repeated flasks fermentation results (data not shown). As shown in Figure 3, when using ammonium nitrate as nitrogen source, the highest viable cells number reached 7.9×1011 CFU/mL, which was 18 and 46 fold higher than that when the peptone and rapeseed meal were used as nitrogen sources, respectively (Figure 3A); however, the iturin A production was the lowest and the maximum iturin A concentration was only 0.06 g/L (Fig. 3B). Among the three nitrogen sources, rapeseed meal was most suitable for iturin A production, the highest iturin A concentration reached 0.60 g/L at 72 h, which was 20% and 10-fold higher than that when peptone and ammonium nitrate were used as nitrogen source, respectively. This result indicates that nitrogen source from complex origin such as rapeseed meal and peptone well promoted the production of iturin A whereas the inorganic ammonium nitrate did not. Clearly, the N-availability of organic or inorganic origins has played different roles in iturin A synthesis. It is postulated that the inorganic N is available to increase the cell numbers but may not last for supporting the formation of secondary metabolites including iturin A in later phases. This finding is consistent with the result reported by Mizumoto and Shoda [30].


Direct bio-utilization of untreated rapeseed meal for effective iturin A production by Bacillus subtilis in submerged fermentation.

Jin H, Zhang X, Li K, Niu Y, Guo M, Hu C, Wan X, Gong Y, Huang F - PLoS ONE (2014)

Time courses of the number of viable cells (A), iturin A concentration (B), reducing sugar (C) and soluble protein concentration (D) with different nitrogen sources in bioreactor batch fermentation.•: rapeseed meal; ▪: peptone; ▴: ammonium nitrate. Error bars represent the standard deviation of the means (N = 3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215929&req=5

pone-0111171-g003: Time courses of the number of viable cells (A), iturin A concentration (B), reducing sugar (C) and soluble protein concentration (D) with different nitrogen sources in bioreactor batch fermentation.•: rapeseed meal; ▪: peptone; ▴: ammonium nitrate. Error bars represent the standard deviation of the means (N = 3).
Mentions: To further investigate the application potential of low-cost rapeseed meal as nitrogen source on iturin A production, two different commercial nitrogen sources, peptone and ammonium nitrate, were applied in batch fermentations to compare the production performance of iturin A with that produced from rapeseed meal in a 7-L bioreactor. The optimal concentrations of peptone and ammonium nitrate were finalized at 30 and 8 g/L, respectively, based on our repeated flasks fermentation results (data not shown). As shown in Figure 3, when using ammonium nitrate as nitrogen source, the highest viable cells number reached 7.9×1011 CFU/mL, which was 18 and 46 fold higher than that when the peptone and rapeseed meal were used as nitrogen sources, respectively (Figure 3A); however, the iturin A production was the lowest and the maximum iturin A concentration was only 0.06 g/L (Fig. 3B). Among the three nitrogen sources, rapeseed meal was most suitable for iturin A production, the highest iturin A concentration reached 0.60 g/L at 72 h, which was 20% and 10-fold higher than that when peptone and ammonium nitrate were used as nitrogen source, respectively. This result indicates that nitrogen source from complex origin such as rapeseed meal and peptone well promoted the production of iturin A whereas the inorganic ammonium nitrate did not. Clearly, the N-availability of organic or inorganic origins has played different roles in iturin A synthesis. It is postulated that the inorganic N is available to increase the cell numbers but may not last for supporting the formation of secondary metabolites including iturin A in later phases. This finding is consistent with the result reported by Mizumoto and Shoda [30].

Bottom Line: A significant promoting effect of rapeseed meal on iturin A production was observed and the maximum iturin A concentration of 0.60 g/L was reached at 70 h, which was 20% and 8.0 fold higher than that produced from peptone and ammonium nitrate media, respectively.Moreover, compared to raw rapeseed meal, the remaining residue following fermentation could be used as a more suitable supplementary protein source for animal feed because of the great decrease of major anti-nutritional components including sinapine, glucosinolate and its degradation products of isothiocyanate and oxazolidine thione.The results obtained from this study demonstrate the potential of direct utilization of low cost rapeseed meal as a nitrogen source for commercial production of iturin A and other secondary metabolites by Bacillus subtilis.

View Article: PubMed Central - PubMed

Affiliation: Oil Crops Research Institute, Chinese Academy of Agriculture Sciences, Wuhan, China; Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, China.

ABSTRACT
The feasibility of using untreated rapeseed meal as a nitrogen source for iturin A production by Bacillus subtilis 3-10 in submerged fermentation was first evaluated by comparison with two different commercial nitrogen sources of peptone and ammonium nitrate. A significant promoting effect of rapeseed meal on iturin A production was observed and the maximum iturin A concentration of 0.60 g/L was reached at 70 h, which was 20% and 8.0 fold higher than that produced from peptone and ammonium nitrate media, respectively. It was shown that rapeseed meal had a positive induction effect on protease secretion, contributing to the release of soluble protein from low water solubility solid rapeseed meal for an effective supply of available nitrogen during fermentation. Moreover, compared to raw rapeseed meal, the remaining residue following fermentation could be used as a more suitable supplementary protein source for animal feed because of the great decrease of major anti-nutritional components including sinapine, glucosinolate and its degradation products of isothiocyanate and oxazolidine thione. The results obtained from this study demonstrate the potential of direct utilization of low cost rapeseed meal as a nitrogen source for commercial production of iturin A and other secondary metabolites by Bacillus subtilis.

Show MeSH