title: Strain screening, fermentation, separation, and encapsulation for production of nattokinase functional food.
abstract: This study presents a novel and integrated preparation technology for nattokinase functional food, including strain screening, fermentation, separation, and encapsulation. To rapidly screen a nattokinase-productive strain, PCR-based screening method was combined with fibrinolytic activity-based method, and a high productive strain, Bacillus subtilis LSSE-22, was isolated from Chinese soybean paste. Reduction of poly-γ-glutamic acid (γ-PGA) concentration may contribute to separation of nattokinase and reduction of late-onset anaphylaxis risk. Chickpeas were confirmed as the favorable substrate for enhancement of nattokinase production and reduction of γ-PGA yield. Using cracked chickpeas, the nattokinase activity reached 356.25 ± 17.18 FU/g (dry weight), which is much higher than previous reports. To further reduce γ-PGA concentration, ethanol fractional extraction and precipitation were applied for separation of nattokinase. By extraction with 50 % and precipitation with 75 % ethanol solution, 4,000.58 ± 192.98 FU/g of nattokinase powders were obtained, and the activity recovery reached 89 ± 1 %, while γ-PGA recovery was reduced to 21 ± 2 %. To improve the nattokinase stability at acidic pH condition, the nattokinase powders were encapsulated, and then coated with methacrylic acid-ethyl acrylate copolymer. After encapsulation, the nattokinase was protected from being denatured under various acid conditions, and pH-responsible controlled release at simulated intestinal fluid was realized.
authors.affiliation: Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Xuetuan
authors.initials: X
authors.lastname: Wei
authors.forename: Mingfang
authors.initials: M
authors.lastname: Luo
authors.forename: Yuchun
authors.initials: Y
authors.lastname: Xie
authors.forename: Liangrong
authors.initials: L
authors.lastname: Yang
authors.forename: Haojian
authors.initials: H
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.forename: Huizhou
authors.initials: H
authors.lastname: Liu
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000302:isolation & purification* / Q000378:metabolism*; D001483:Base Sequence; D002214:Capsules; D011232:Chemical Precipitation; D029863:Cicer / Q000201:enzymology / Q000382:microbiology*; D004795:Enzyme Stability; D000431:Ethanol / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D005285:Fermentation; D005342:Fibrinolysis; D005780:Gelatin / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011109:Polymethacrylic Acids / Q000737:chemistry; D013025:Glycine max / Q000201:enzymology / Q000382:microbiology*; D013381:Subtilisins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000179:Acrylates; D002214:Capsules; D011109:Polymethacrylic Acids; D014867:Water; C030613:polymethacrylic acid; D000431:Ethanol; C040833:ethyl acrylate; D005780:Gelatin; D013381:Subtilisins; C053771:nattokinase