摘要
研究米根霉HB12利用玉米淀粉生产乳酸的发酵条件优化。从土壤中新筛选得到一株以高浓度玉米淀粉为原料发酵生产乳酸的米根霉HB12。通过单因素及正交试验,得到最佳发酵培养基组成(g/L)为:玉米淀粉140、NH4Cl 2、KH2PO4 0.3、MgSO4.7H2O 0.3、ZnSO4.7H2O 0.05、CaCO3 80;最佳培养条件为:摇瓶装液量50mL/250mL,接种量为2.5×106个孢子,35℃、200r/min培养108h。该条件下,菌株最大产酸量为104.9g/L,产酸速率为0.97g/(L.h),对玉米淀粉的转化率达74.9%,产酸量提高了49.4%。此菌株能够直接高效利用价格低廉来源广泛的玉米淀粉发酵生产乳酸,具有很好的工业应用前景。
The fermentation conditions of lactic acid produced from corn starch by Rhizopus oryzae were investigated. Rhizopus oryzae HB 12 was newly isolated from soil samples. Based on single factor and orthogonal tests, the optimal fermenttation medium was composed of 140 g/L corn starch, 2 g/L NH4C1, 0.3 g/L KH2PO4, 0.3 g/L MgSO4· 7H2O, 0.05 g/L ZnSO4·7H2O and 80 g/L CaCO3. The optimal fermentation conditions were 2.5 ×10^6 spores in 50 mL of medium cultured at 35 ℃, 200 r/min shaking for 108 h in 250 mL flask. Under the optimal fermentation conditions, the yield of lactic acid produced from corn starch was up to 104.9 g/L with a conversion of 74.9%. The volumetric production rate was up to 0.97 g/（L· h）, which revealed 49.4% enhancement compared with the original conditions. Therefore, Rhizopus oryzae HB12 can effectively utilize inexpensive corn starch for the production of lactic acid, which will have good prospect for industrial application.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2012年第5期150-154,共5页
Food Science
基金
国家"973"计划项目(2007CB714304)
关键词
米根霉
乳酸
发酵条件
玉米淀粉
Rhizopus oryzae
lactic acid
fermentation condition
corn starch
