This work aimed to explore an effective way for converting agro-industrial residues into value-added products.A thermophilic protease-producing strain was isolated from soybean meal(SBM)and identified as Bacillus lich...This work aimed to explore an effective way for converting agro-industrial residues into value-added products.A thermophilic protease-producing strain was isolated from soybean meal(SBM)and identified as Bacillus licheniformis by 16S rDNA sequencing.After incubating Bacillus licheniformis CPB2 in casein medium for 24 h,the protease activity,peptide yield,and protein conversion rate of the culture could reach 8.87±0.33 U/mL,68.58%,and 82.27%,respectively.Brewer’s spent grain(BSG)and SBM were used as co-substrates to produce value-added peptides through thermophilic solid-state fermentation(TSSF)with Bacillus licheniformis CPB2.The peptide content of the co-substrates increased from 25.71 mg/g to 112.72 mg/g under the optimal TSSF conditions.The fermented products showed an increased crude protein and free amino acids contents and a decreased crude fat and ash contents as well as trypsin inhibitor activity compared with the unfermented co-substrates.TSSF could degrade macromolecular proteins into peptides,unfold the protein aggregates,and reduce the particle size.Industrial relevance:This work proposed an effective way for the rational and efficient utilization of wet and dry agro-industrial residues to produce value-added products,which showed a broad potential for reducing production costs,saving water resources and energy,and preserving the ecological environment.展开更多
Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened...Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened protease-producing bacteria from the South China Sea sediments and analyzed the diversity of their extracellular proteases at the family level through N-terminal amino acid sequencing. Results of the 16 S rRNA gene sequence analysis showed that all screened protease-producing bacteria belonged to the class Gammaproteobacteria and most of them were affiliated with different genera within the orders Alteromonadales and Vibrionales. The Nterminal amino acid sequence analysis for fourteen extracellular proteases from fourteen screened bacterial strains revealed that all these proteases belonged to the M4 family of metalloproteases or the S8 family of serine proteases. This study presents new details on taxa of marine sedimentary protease-producing bacteria and types of their extracellular proteases, which will help to comprehensively understand the process and mechanism of the microbial enzymatic degradation of marine sedimentary organic nitrogen.展开更多
基金financial support provided by the Key R&D Plan of Jiangsu Province(Key Project of Modern Agriculture,grant BE2016355).
文摘This work aimed to explore an effective way for converting agro-industrial residues into value-added products.A thermophilic protease-producing strain was isolated from soybean meal(SBM)and identified as Bacillus licheniformis by 16S rDNA sequencing.After incubating Bacillus licheniformis CPB2 in casein medium for 24 h,the protease activity,peptide yield,and protein conversion rate of the culture could reach 8.87±0.33 U/mL,68.58%,and 82.27%,respectively.Brewer’s spent grain(BSG)and SBM were used as co-substrates to produce value-added peptides through thermophilic solid-state fermentation(TSSF)with Bacillus licheniformis CPB2.The peptide content of the co-substrates increased from 25.71 mg/g to 112.72 mg/g under the optimal TSSF conditions.The fermented products showed an increased crude protein and free amino acids contents and a decreased crude fat and ash contents as well as trypsin inhibitor activity compared with the unfermented co-substrates.TSSF could degrade macromolecular proteins into peptides,unfold the protein aggregates,and reduce the particle size.Industrial relevance:This work proposed an effective way for the rational and efficient utilization of wet and dry agro-industrial residues to produce value-added products,which showed a broad potential for reducing production costs,saving water resources and energy,and preserving the ecological environment.
基金The AoShan Talents Cultivation Program supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2017ASTCP-OS14the National Natural Science Foundation of China under contract Nos 31670063,31670497 and 31870052+1 种基金the Taishan Scholars Program of Shandong Province under contract No.2009TS079the Science and Technology Basic Resources Investigation Program of China under contract No.2017FY100804
文摘Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened protease-producing bacteria from the South China Sea sediments and analyzed the diversity of their extracellular proteases at the family level through N-terminal amino acid sequencing. Results of the 16 S rRNA gene sequence analysis showed that all screened protease-producing bacteria belonged to the class Gammaproteobacteria and most of them were affiliated with different genera within the orders Alteromonadales and Vibrionales. The Nterminal amino acid sequence analysis for fourteen extracellular proteases from fourteen screened bacterial strains revealed that all these proteases belonged to the M4 family of metalloproteases or the S8 family of serine proteases. This study presents new details on taxa of marine sedimentary protease-producing bacteria and types of their extracellular proteases, which will help to comprehensively understand the process and mechanism of the microbial enzymatic degradation of marine sedimentary organic nitrogen.
