Process for producing cysteine and/or glutathione from cystine employing yeast
A technology of cysteine and glutathione, applied in fermentation, application, food preparation, etc., can solve problems such as expensive and complicated methods
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Embodiment 1
[0025] Cysteine production during yeast autolysis
[0026] Yeast extract from Saccharomyces cerevisiae (18.2% dry solids) was autolyzed at pH 5.9 and 51°C by adding endoprotease from Bacillus licheniformis (Alcalase, Novozymes, Denmark). During autolysis, according to Table 1, cystine (2% w / w), reduced nicotinamide adenine dinuclear Nucleic acid (NADH, 1% w / w) and / or glucose (1% w / w), both added w / w based on total dry weight.
[0027] After 20 hours of autolysis, solid-liquid separation was accomplished by centrifugation without pH adjustment. The yield on dry matter was 70%. Supernatants containing soluble fractions from yeast cells were analyzed for cysteine content (mg / g dry matter) using NMR and HPLC. The results are listed in Table 1.
[0028] Table 1 Cysteine content of supernatant
[0029] experiment
Embodiment 2
[0031] Cysteine Production by Yeast Cell Wall and Yeast Extract
[0032] Approximately 2 kg of yeast extract from Saccharomyces cerevisiae (yeast suspension with a dry solids content of 19.9% w / w) was heat treated at 51° C. for 5 min. The pH of the suspension was then adjusted to 6.0 using NaOH. The autolysate was obtained by autolysing the yeast suspension by adding Bacillus subtilus serine endoprotease (obtained as Alcalase, Novozymes, Denmark) in an amount of 0.0068 g / g on dry matter basis and incubating for 3.5 h. Then use H 2 SO 4 The pH of the autolysate was brought down to 5.1 and the autolysate was incubated for approximately 18 h. Next, the autolysate was centrifuged at 4400 rpm for 15 min, resulting in a cell wall containing pellet and yeast extract supernatant. The pellet was washed twice with cold water, resuspended in water, and centrifuged under the same conditions. The supernatant was discarded and the cell wall containing pellet was resuspended in wate...
Embodiment 3
[0038] Cysteine is produced during fermentation
[0039] Saccaromyces cerevisiae was grown on inorganic medium according to Table 3 in 100 ml shake flasks. Vitamins, cofactors and trace elements are added separately.
[0040] Table 3 Medium composition (unless otherwise indicated in g / 500mL)
[0041] compound
quantity
NH 4 h 2 PO 4
30
MgCl 2 .6aq
2
NH 4 Cl
8.1
K H 2 PO 4
5
NaCl
0.5
CaCl 2 (1M) *
4,5mL
[0042] * Add from 1M stock solution after medium sterilization
[0043] The medium was heat sterilized at 160°C for 180 minutes. The incubation temperature was 30°C and the fermentation time was 24 hours. Each bottle was fermented in duplicate (A and B). Other conditions are listed in Table 4. Cysteine and cystine were added according to Table 5.
[0044] Table 4 fermentation conditions
[0045] baffle
No
obstruction
wate...
PUM
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