Direct Bio-Utilization of Untreated Rapeseed Meal for Effective Iturin A Production by Bacillus subtilis in Submerged Fermentation

PLOS ONE, Dec 2019

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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Direct Bio-Utilization of Untreated Rapeseed Meal for Effective Iturin A Production by Bacillus subtilis in Submerged Fermentation

et al. (2014) Direct Bio-Utilization of Untreated Rapeseed Meal for Effective Iturin A Production by Bacillus subtilis in Submerged Fermentation. PLoS ONE 9(10): e111171. doi:10.1371/journal.pone.0111171 Direct Bio-Utilization of Untreated Rapeseed Meal for Effective Iturin A Production by Bacillus subtilis in Submerged Fermentation Hu Jin 0 Xinran Zhang 0 Kunpeng Li 0 Yanxing Niu 0 Mian Guo 0 Chuanjiong Hu 0 Xia Wan 0 Yangmin Gong 0 Fenghong Huang 0 Jonathan A. Coles, Glasgow University, United Kingdom 0 1 Oil Crops Research Institute, Chinese Academy of Agriculture Sciences , Wuhan , China , 2 Hubei Key Laboratory of Lipid Chemistry and Nutrition , Wuhan , China , 3 College of Life Science, Hubei University , Wuhan , China 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. - Funding: This work was supported by the National Natural Science Foundation of China (No. 31201461), National High-tech R&D Program of China (863 Program, No. 2011AA100904), National Key Technology Research and Development Program (No. 2012BAD49G00), and Director Fund of Oil Crops Research Institute (Nos. 1610172014006, 1610172013005). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. The increasing demand for a steady, healthy food supply requires an efficient control of major plant pests and diseases [1]. Currently, conventional crop management practices are based largely on the application of synthetic pesticides, which have caused serious environmental and health problems. Moreover, the efficacy of synthetic pesticides is gradually decreasing due to the adaptation and resistance of pathogens to these pesticides [2]. One of the greatest ecological challenges in the near future is to develop environmentally friendly alternatives [3]. Recently, biological control agents have received considerable attention as alternatives to chemical pesticides for plant diseases and are considered to be one of the most promising methods for rational and safe cropmanagement practices [4]. Bacillus subtilis, one of the most commonly used and well-studied microbial species, has the potential to produce more than two dozen structurally diverse antimicrobial compounds with broad inhibitory spectrum and high viability [5]. Among these antimicrobial compounds, cyclic lipopeptides of iturin, surfactin and fengycin families have wellrecognized potential uses in biotechnology and biopharmaceutical applications because of their excellent surfactant properties. Iturin A is a cyclic lipopeptide antibiotic with the structure of a cyclic heptapeptide linked to a 1417 carbons b-amino fatty acid chain [3]. This special structure endows it with strong antifungal action because of its membrane permeable properties [6]. It is a potential weapon for controlling plant diseases caused by phytopathogenic fungi. However, a significant obstacle to largescale industrial application of cyclic lipopeptide antibiotics such as iturin A is the high production cost coupled with a low production rate. If the production costs of these cyclic lipopeptide antibiotics become competitive with the synthetic chemical pesticides, their industrial use might be expected to grow tremendously in the coming decade [7]. In order to achieve this goal, recent efforts have been focused on the reduction of lipopeptide antibiotics production costs through improving the yield and utilization of low-cost feedstocks, such as soybean curd residue [8], soybean and sweet potato residues [9], cassava flour wastewater [10,11], synthetic wastewater [12] and waste soybean oil [13]. However, n (...truncated)


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Hu Jin, Xinran Zhang, Kunpeng Li, Yanxing Niu, Mian Guo, Chuanjiong Hu, Xia Wan, Yangmin Gong, Fenghong Huang. Direct Bio-Utilization of Untreated Rapeseed Meal for Effective Iturin A Production by Bacillus subtilis in Submerged Fermentation, PLOS ONE, 2014, 10, DOI: 10.1371/journal.pone.0111171