Alpha-lactalbumin(α-LA)is a major whey protein found in breast milk and plays a crucial role in the growth and development of infants.In this study,Bacillus subtilis RIK1285 harboring AprE signal peptide(SP)was selec...Alpha-lactalbumin(α-LA)is a major whey protein found in breast milk and plays a crucial role in the growth and development of infants.In this study,Bacillus subtilis RIK1285 harboring AprE signal peptide(SP)was selected as the original strain for the production ofα-LA.It was found thatα-LA was identified in the pellet after ultrasonic disruption and centrifugation instead of in the fermentation supernatant.The original strain most likely only producedα-LA intracellular,but not extracellular.To improve the expression and secretion ofα-LA in RIK1285,a library of 173 homologous SPs from the B.subtilis 168 genome was fused with target LALBA gene in the pBE-S vector and expressed extracellularly in RIK1285.SP YjcN was determined to be the best signal peptide.Bands in supernatant were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and purified by nickel column to calculate the highest yield signal peptide.In addition,different promoters(P_(aprE),P_(43),and P_(glv))were compared and applied.The results indicated that the strain RIK1285-pBE-P_(glv)-YjcN-LALBA had the highestα-LA yield,reaching 122.04μg/mL.This study demonstrates successful expression and secretion of humanα-LA in B.subtilis and establishes a foundation for simulating breast milk for infant formulas and developing bioengineered milk.展开更多
In this study,we proposed a reliable and sustainable technique for the clean utilization of shrimp wastes,which can yield a solid inoculant of Bacillus subtilis OKF04 containing micronutrients at low cost without the ...In this study,we proposed a reliable and sustainable technique for the clean utilization of shrimp wastes,which can yield a solid inoculant of Bacillus subtilis OKF04 containing micronutrients at low cost without the risk of contamination.Study of the culture conditions revealed that the head of shrimp Litopenaus vannamei and the wheat bran acted as suitable substrates for the growth of B.subtilis OKF04.With 60%initial moisture content,30℃culture temperature,and 5%inoculation amount,followed by 48 hours of fermentation and 0.5%soluble starch added during the drying process(50℃for 6h),a solid B.subtilis OKF04 inoculant with a spore amount of 2.4×10^(10)CFU g^(-1)and a high amino acid content was obtained.The solid B.subtilis OKF04 inoculant was applied to cultivate pakchoi under pot experiment.As the result,of adding to,the size of stems and leaves,nutritional composition,and physiological activity of pakchoi were significantly(P<0.05)enhanced by solid B.subtilis OKF04 inoculant.B.subtilis OKF04 also significantly(P<0.05)increased the soil’s nutrient content and improved its microbial composition.Furthermore,pakchoi cultivated with a low dose of solid B.subtilis OKF04 inoculant(0.05 g kg^(-1)soil)resulted in the best results.This study provides a new method for the preparation of microbial inoculants with solid waste shrimp heads.展开更多
The aim of our study was to use a biosurfactant produced by Bacillus and Lactobacillus isolates as an antiseptic in the formulation of local soap. A total of 60 isolates were characterized by microbiological technique...The aim of our study was to use a biosurfactant produced by Bacillus and Lactobacillus isolates as an antiseptic in the formulation of local soap. A total of 60 isolates were characterized by microbiological techniques (30 Bacillus and 30 Lactobacillus) and the ability to produce biosurfactants was demonstrated by a hydrocarbon emulsification index (E24). The emulsification indexes (E24) varied from 9% to 100% for Bacillus and from 33% to 100% for Lactobacillus as well. The antagonistic assay showed that biosurfactants were able to inhibit the formation of biofilms and growth of pathogens such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella typhirium, Shigella boydii and Proteus mirabilis. The biosurfactant consortium (BioC) from Bacillus consortium and from Lactobacillus was able to inhibit biofilm formation and the pathogens growth. The BioC was stable to alkaline pH and the temperatures stability of Biosurfactant was ranging from 50°C to 90°C. The soap was made by the cold saponification process using one biosurfactant consortium formulated. This soap has a pH of 10 and showed good cleaning power and good foam stability. Similarly, the soap showed good antiseptic power and disinfection power against all pathogens tested. Handwashing is critical to preventing disease transmission. The persistence of pathogens in waste water was evaluated. The BioS produced showed good disinfection power against all pathogens tested. The valor of reduction on the hands and in the waste water was significantly more than compared to the control soaps used. This soap could be used in the prevention, fighting, and treatment of bacterial and viral infections.展开更多
基金This work was funded by National Natural Science Foundation of China(32272279)the Key R&D project of Qingdao Science and Technology Plan(22-3-3-hygg-29-hy).
文摘Alpha-lactalbumin(α-LA)is a major whey protein found in breast milk and plays a crucial role in the growth and development of infants.In this study,Bacillus subtilis RIK1285 harboring AprE signal peptide(SP)was selected as the original strain for the production ofα-LA.It was found thatα-LA was identified in the pellet after ultrasonic disruption and centrifugation instead of in the fermentation supernatant.The original strain most likely only producedα-LA intracellular,but not extracellular.To improve the expression and secretion ofα-LA in RIK1285,a library of 173 homologous SPs from the B.subtilis 168 genome was fused with target LALBA gene in the pBE-S vector and expressed extracellularly in RIK1285.SP YjcN was determined to be the best signal peptide.Bands in supernatant were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and purified by nickel column to calculate the highest yield signal peptide.In addition,different promoters(P_(aprE),P_(43),and P_(glv))were compared and applied.The results indicated that the strain RIK1285-pBE-P_(glv)-YjcN-LALBA had the highestα-LA yield,reaching 122.04μg/mL.This study demonstrates successful expression and secretion of humanα-LA in B.subtilis and establishes a foundation for simulating breast milk for infant formulas and developing bioengineered milk.
基金the China Agriculture Research System of MOF and MARA(No.CARS-48)the Taishan Scholar Project of Shandong Province(No.tsqn201812020)。
文摘In this study,we proposed a reliable and sustainable technique for the clean utilization of shrimp wastes,which can yield a solid inoculant of Bacillus subtilis OKF04 containing micronutrients at low cost without the risk of contamination.Study of the culture conditions revealed that the head of shrimp Litopenaus vannamei and the wheat bran acted as suitable substrates for the growth of B.subtilis OKF04.With 60%initial moisture content,30℃culture temperature,and 5%inoculation amount,followed by 48 hours of fermentation and 0.5%soluble starch added during the drying process(50℃for 6h),a solid B.subtilis OKF04 inoculant with a spore amount of 2.4×10^(10)CFU g^(-1)and a high amino acid content was obtained.The solid B.subtilis OKF04 inoculant was applied to cultivate pakchoi under pot experiment.As the result,of adding to,the size of stems and leaves,nutritional composition,and physiological activity of pakchoi were significantly(P<0.05)enhanced by solid B.subtilis OKF04 inoculant.B.subtilis OKF04 also significantly(P<0.05)increased the soil’s nutrient content and improved its microbial composition.Furthermore,pakchoi cultivated with a low dose of solid B.subtilis OKF04 inoculant(0.05 g kg^(-1)soil)resulted in the best results.This study provides a new method for the preparation of microbial inoculants with solid waste shrimp heads.
文摘The aim of our study was to use a biosurfactant produced by Bacillus and Lactobacillus isolates as an antiseptic in the formulation of local soap. A total of 60 isolates were characterized by microbiological techniques (30 Bacillus and 30 Lactobacillus) and the ability to produce biosurfactants was demonstrated by a hydrocarbon emulsification index (E24). The emulsification indexes (E24) varied from 9% to 100% for Bacillus and from 33% to 100% for Lactobacillus as well. The antagonistic assay showed that biosurfactants were able to inhibit the formation of biofilms and growth of pathogens such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella typhirium, Shigella boydii and Proteus mirabilis. The biosurfactant consortium (BioC) from Bacillus consortium and from Lactobacillus was able to inhibit biofilm formation and the pathogens growth. The BioC was stable to alkaline pH and the temperatures stability of Biosurfactant was ranging from 50°C to 90°C. The soap was made by the cold saponification process using one biosurfactant consortium formulated. This soap has a pH of 10 and showed good cleaning power and good foam stability. Similarly, the soap showed good antiseptic power and disinfection power against all pathogens tested. Handwashing is critical to preventing disease transmission. The persistence of pathogens in waste water was evaluated. The BioS produced showed good disinfection power against all pathogens tested. The valor of reduction on the hands and in the waste water was significantly more than compared to the control soaps used. This soap could be used in the prevention, fighting, and treatment of bacterial and viral infections.
