The debittering effect of extracellular enzymes from Bacillus subtilis ACCC 01746 was studied using soybean meal as a substrate for solid-state fermentation(SSF).Results showed that B.subtilis produces proteases and c...The debittering effect of extracellular enzymes from Bacillus subtilis ACCC 01746 was studied using soybean meal as a substrate for solid-state fermentation(SSF).Results showed that B.subtilis produces proteases and carboxypeptidase in the early stage of SSF(0–8 h).Proteases are dominant and can hydrolyze the soybean protein into long-chain peptides with mild bitterness.Carboxypeptidase production is dominant at 8–16 h SSF,at which point soybean protein is further hydrolyzed and bitterness is enhanced.The strain then produces additional carboxypeptidase after 16 h,and bitterness is reduced.We compared the amino acid composition of the hydrolysates from soybean protein isolates to that of the fermented liquid of SSF.In the hydrolysates from soybean protein isolates that exhibit strong bitterness,62.81%of amino acids are hydrophobic and occur in the form of peptides.In the fermented liquid from soybean meal,16.22%of amino acids are hydrophobic and are mainly present in the form of free amino acids.The bitterness of fermented soybean hydrolysate is reduced from 5 to 0 when fermented for 24 h,suggesting that B.subtilis can effectively reduce bitterness,possibly due to the carboxypeptidase.Enzyme analysis shows that B.subtilis excretes carboxypeptidase during growth.The amino acids phenylalanine,alanine,tyrosine,and leucine at the C-terminal of the soybean bitter peptides in hydrolysates are cleaved in the presence of carboxypeptidase,resulting in complete debitterness.展开更多
Soybean meal （SBM） is commonly used for livestock feeds, but its application in diets for livestock is limited due to some antinutritional factors. The contents of methionine and lysine of soybean meal were promoted...Soybean meal （SBM） is commonly used for livestock feeds, but its application in diets for livestock is limited due to some antinutritional factors. The contents of methionine and lysine of soybean meal were promoted by Bacillus natto and Leuconostoc mesenteroides fermentation, benefial for the livestock feeds. It was crude protein （CP） 56.8%, methionine 43.56 mg · g^-1, and lysine 74.87 mg · g^-1, cows fed a diet with FSBM milk yield raised 14.2%, the change in the milk protein, the lactose and the dry matter content had also obvious increase. This convenient technique offers helpful exploration for industrialization of soybean meal fermentation.展开更多
Methionine （Met） and lysine （Lys） have been reported as the first two limiting amino acids （AA） for maximum milk yield and milk protein production. Supplying these AA may improve microbial protein synthesis and ...Methionine （Met） and lysine （Lys） have been reported as the first two limiting amino acids （AA） for maximum milk yield and milk protein production. Supplying these AA may improve microbial protein synthesis and therefore improve milk production without adding excess N to the environment. This observation utilized fermented soybean meal （SBM）, cottonseed meal （CSM）, rapeseed meal （RSM） and corn by Bacillus subtilis 168 and Leuconostoc mesenteroides as core feedstuffs to produce special biological protein feed for dairy cow. The results showed that the milk production, milk protein percentage, milk fat percentage and milk DM percentage of test groups in trial period were significantly more than those of the control group （P〈0.01）, the results showed that adding fermenting protein feed in dairy cow diets could significantly improve milk yield, milk protein and milk fat content. The economic benefits of actual application were analyzed, the group of 0.5% was the best compared with the other groups.展开更多
基金supported by Grain&Corn Engineering Technology Research Center,State Administration of Grain(GA2017004)Science and Technology Research Project of Henan(172102110205)Henan University of Technology:Integration of Science and Education(30)
文摘The debittering effect of extracellular enzymes from Bacillus subtilis ACCC 01746 was studied using soybean meal as a substrate for solid-state fermentation(SSF).Results showed that B.subtilis produces proteases and carboxypeptidase in the early stage of SSF(0–8 h).Proteases are dominant and can hydrolyze the soybean protein into long-chain peptides with mild bitterness.Carboxypeptidase production is dominant at 8–16 h SSF,at which point soybean protein is further hydrolyzed and bitterness is enhanced.The strain then produces additional carboxypeptidase after 16 h,and bitterness is reduced.We compared the amino acid composition of the hydrolysates from soybean protein isolates to that of the fermented liquid of SSF.In the hydrolysates from soybean protein isolates that exhibit strong bitterness,62.81%of amino acids are hydrophobic and occur in the form of peptides.In the fermented liquid from soybean meal,16.22%of amino acids are hydrophobic and are mainly present in the form of free amino acids.The bitterness of fermented soybean hydrolysate is reduced from 5 to 0 when fermented for 24 h,suggesting that B.subtilis can effectively reduce bitterness,possibly due to the carboxypeptidase.Enzyme analysis shows that B.subtilis excretes carboxypeptidase during growth.The amino acids phenylalanine,alanine,tyrosine,and leucine at the C-terminal of the soybean bitter peptides in hydrolysates are cleaved in the presence of carboxypeptidase,resulting in complete debitterness.
基金Supported by Science and Technology Foundation (GB08B401-02)Science and Technology for Youth in Heilongjiang Province (QC07C35)
文摘Soybean meal （SBM） is commonly used for livestock feeds, but its application in diets for livestock is limited due to some antinutritional factors. The contents of methionine and lysine of soybean meal were promoted by Bacillus natto and Leuconostoc mesenteroides fermentation, benefial for the livestock feeds. It was crude protein （CP） 56.8%, methionine 43.56 mg · g^-1, and lysine 74.87 mg · g^-1, cows fed a diet with FSBM milk yield raised 14.2%, the change in the milk protein, the lactose and the dry matter content had also obvious increase. This convenient technique offers helpful exploration for industrialization of soybean meal fermentation.
基金Supported by"863"Project of Ministry of Science and Technology of China(2013AA102504-03)
文摘Methionine （Met） and lysine （Lys） have been reported as the first two limiting amino acids （AA） for maximum milk yield and milk protein production. Supplying these AA may improve microbial protein synthesis and therefore improve milk production without adding excess N to the environment. This observation utilized fermented soybean meal （SBM）, cottonseed meal （CSM）, rapeseed meal （RSM） and corn by Bacillus subtilis 168 and Leuconostoc mesenteroides as core feedstuffs to produce special biological protein feed for dairy cow. The results showed that the milk production, milk protein percentage, milk fat percentage and milk DM percentage of test groups in trial period were significantly more than those of the control group （P〈0.01）, the results showed that adding fermenting protein feed in dairy cow diets could significantly improve milk yield, milk protein and milk fat content. The economic benefits of actual application were analyzed, the group of 0.5% was the best compared with the other groups.
