以大豆黄浆水为原料,选用白地霉、扣囊拟内孢霉、解脂假丝酵母和产朊假丝酵母(2∶1∶1∶2)作为发酵菌株发酵黄浆水。在单因素试验的基础上,通过响应面设计法,对黄浆水发酵生产单细胞蛋白(SCP)的工艺进行研究。结果表明,影响SCP产量的因...以大豆黄浆水为原料,选用白地霉、扣囊拟内孢霉、解脂假丝酵母和产朊假丝酵母(2∶1∶1∶2)作为发酵菌株发酵黄浆水。在单因素试验的基础上,通过响应面设计法,对黄浆水发酵生产单细胞蛋白(SCP)的工艺进行研究。结果表明,影响SCP产量的因素大小顺序为初始p H、发酵时间、装液量;最佳发酵工艺参数为碳氮比5、初始p H 6、装液量140 m L/250 m L、接种量6%、发酵温度28℃、发酵时间42 h;经过优化后的SCP产量达到3.28 g/100 m L。展开更多
An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentat...An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentation and to increase the crystallization efficiency of IA from the fermentation broth. The glucose （GS） syrups saccharified by several combinations of glucoamylase and pullulanase were investigated and used as the carbohydrate source of the fermentation medium for the spore-initiated submerged fermentations experiments. Compared with the conventional process （with pullulanase controlled）, the improved process decreased th.e RS residue in the fermentation broth from 3.01g/L to 1.35g/L and from 4.25g/L to 3.25g/L when the original RS of the medium were 100 and 120g/L, respectively. The crystallization efficiency of IA increased from 65% to 78.8% and from 69.58% to 82.81% with the original RS being 100 and 120g/L, respectively.展开更多
Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydro- lysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 9700 o...Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydro- lysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 9700 of the granules was hydrolysized with diameter between 0.15 mm and 0.3 mm at 50 ℃. When corn starch concentration increased from 100 g/L to 250 g/L, the amount of reducing sugar produced was proportional to the initial substrate concentration and no substrate inhibition phenomenon appeared. In order to study the product inhibition exactly, the product from hydrolysis reaction itself was added into the hydrolysis system at the beginning of starch hydrolysis. Product inhibition with different quantities of product added were studied in the initial several hours, during which period enzyme inactivation could be neglected and product inhibition could be studied separately. The experiments indicate that product inhibition happens when the additional quantity exceeds 9.56 g/L.展开更多
文摘以大豆黄浆水为原料,选用白地霉、扣囊拟内孢霉、解脂假丝酵母和产朊假丝酵母(2∶1∶1∶2)作为发酵菌株发酵黄浆水。在单因素试验的基础上,通过响应面设计法,对黄浆水发酵生产单细胞蛋白(SCP)的工艺进行研究。结果表明,影响SCP产量的因素大小顺序为初始p H、发酵时间、装液量;最佳发酵工艺参数为碳氮比5、初始p H 6、装液量140 m L/250 m L、接种量6%、发酵温度28℃、发酵时间42 h;经过优化后的SCP产量达到3.28 g/100 m L。
基金the National Natural Science Foundatioo of China(No.30670566)the International S&T Cooperation Program of China(No.2006DFA33150)
文摘An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentation and to increase the crystallization efficiency of IA from the fermentation broth. The glucose （GS） syrups saccharified by several combinations of glucoamylase and pullulanase were investigated and used as the carbohydrate source of the fermentation medium for the spore-initiated submerged fermentations experiments. Compared with the conventional process （with pullulanase controlled）, the improved process decreased th.e RS residue in the fermentation broth from 3.01g/L to 1.35g/L and from 4.25g/L to 3.25g/L when the original RS of the medium were 100 and 120g/L, respectively. The crystallization efficiency of IA increased from 65% to 78.8% and from 69.58% to 82.81% with the original RS being 100 and 120g/L, respectively.
文摘Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydro- lysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 9700 of the granules was hydrolysized with diameter between 0.15 mm and 0.3 mm at 50 ℃. When corn starch concentration increased from 100 g/L to 250 g/L, the amount of reducing sugar produced was proportional to the initial substrate concentration and no substrate inhibition phenomenon appeared. In order to study the product inhibition exactly, the product from hydrolysis reaction itself was added into the hydrolysis system at the beginning of starch hydrolysis. Product inhibition with different quantities of product added were studied in the initial several hours, during which period enzyme inactivation could be neglected and product inhibition could be studied separately. The experiments indicate that product inhibition happens when the additional quantity exceeds 9.56 g/L.
