Today, although the fermentation approach as well as chemical technique of amino acid production have actually created rapidly, as well as the production cost has dropped, the healthy protein hydrolysis technique for the manufacturing of amino acids has actually been substantially affected, however the manufacturing technique of some amino acids using healthy protein acid hydrolysis still can not be overlooked, such as cystine, cells Numerous amino acids such as amino acid, arginine, leucine, tyrosine, as well as serine are still mainly hydrolyzed. Since our nation is rich in natural protein resources, such as human hair, pig hair, waste silk, and so on are all good resources. Cystine is normally prepared from pig hair or human hair basic materials, acid hydrolysis, separation as well as purification (making use of isoelectric factor rainfall approach). Pig hair or human hair [HCl (hydrolysis)] → [110-117 ℃, 6.5-7h] hydrolyzate [30% -40% NaOH (neutralization)] → [get used to pH4.8, stand for 36h, filter] Crude L-cystine I.
Crude item I [HCl, 1% activated carbon (refined)] → [85 ° C, warm decolorization 0.5 h] filtrate [12% NH4OH (neutralization)] → [gotten used to pH3.5-4] L-cystine.
Hydrolysis In the hydrolysis tank (tank), put 10mol/L HCl1000kg, heat 70-80 ℃, then put in cleaned as well as dried out pig hair or human hair, which has to do with half the amount of hydrochloric acid (500kg), and also continue warming to 100 ℃ Currently, start to change the temperature level, make it rise to 110-117 ° C within 1-1.5 h, heat-preserve and also hydrolyze for 7h (calculated from 100 ° C), discharge and also filter, and also take the filtrate (hydrolyzate). The neutralization hydrolyzate is presented right into the neutralization container, gradually include 30% -40% NaOH remedy as well as maintain stirring, change the hydrolyzate to pH 4.8 and stop adding alkali. Continue to stir for 15 minutes, retest the pH to 4.8 to acquire a counteracting service, allow it represent 36 hrs, filter to gather the precipitate, and also centrifuge to completely dry to obtain crude L-cystine I.
Crude, counteracted, take about 200kg of L-cystine crude item I, include 120kg of 10mol/L HCl service, 480kg of water (800kg in overall), warmth to dissolve, and maintain stirring, when the temperature rises to 80 ° C, include the weight of the unrefined item remedy 2% triggered carbon (concerning 16kg) and also keep warm at 80-90 ° C for 0.5 h, filter to get rid of activated carbon, readjust the pH value of the gotten filtrate with 30% NaOH remedy, keep mixing to make it pH 4.8, as well as let it stand for formation, and afterwards precipitated the supernatant, the bottom precipitated crystals were dried out to obtain unrefined L-cystine II.
Refining and also neutralization Take 50kg of the unrefined product of L-cystine II above, add 250L of 1mol/L HCl service, mix and also warmth to liquify, when the temperature rises to 70 ° C, include activated carbon (3kg) with 1% weight of crude product II hydrochloric acid remedy to heat up Decolorize at 85 ° C for 0.5 h, filter to get rid of turned on carbon, and acquire a colorless and also transparent filtrate. After that include 1.5 times the weight of pure water, warm at 75-80 ° C, stir as well as counteract with 12% ammonia water to pH 3.5-4.0, suck out the mom alcohol above the formation while it is warm, filter the condensation at the bottom, as well as remove the chlorine-free ion with pure water, pump Dry as well as vacuum-dry to obtain L-cystine.