论文部分内容阅读
在离体试验中,不同金属离子对马铃薯软腐欧文氏菌(Erwinia carotovora subsp.carotovora)菌株StEcc-12生长,产生胞外酶和胞外酶活性具有不同的影响。在含果胶酸钠的培养液中,Ca~(2+)促进生长,并使培养液中的果胶裂解酶(PL)、果胶水解酶(PG)和蛋白酶3种胞外酶分别提高1.4～23.4倍,0.3～2.9倍和0.7～6.5倍。Mn~(2+)对StEcc-12生长及产生3种胞外酶的影响与Ca~(2+)相似。Ni~(2+)显著抑制细菌的生长,但在含Ni~(2+)培养液中3种胞外酶的单位活性比对照高1.7倍以上。在酶粗提液中分别加入上述3种离子对PL酶的活性均有抑制作用。Zn~(2+)对细菌生长没有显著影响,高浓度Al~(3+)抑制细菌生长,这2种离子均能促进3种胞外酶的产生。随着Fe~(2+)和K~+浓度的增高,细菌生长减少,两种果胶酶产量降低,蛋白酶产量增加,粗提液中PL酶活性下降。Mg~(2+)对细菌生长和胞外PG产生没有明显影响,提高Mg~(2+)浓度有利于PL的产生。酶粗提液中加入Mg~(2+)后PL活性增高。所有以上离子都能使聚半乳糖醛酸发生不同程度的凝聚,但只有Ca~(2+)和Mg~(2+)的有效凝聚浓度与薯块的实际浓度接近。
In vitro, different metal ions have different effects on the growth, production of extracellular and extracellular enzymes of Erwinia carotovora subsp. Carotovora StEcc-12. In the culture medium containing sodium pectinate, Ca 2+ promoted the growth and increased the extracellular enzymes of pectin lyase (PL), pectinolytic enzyme (PG) and protease in the culture medium 1.4 to 23.4 times, 0.3 to 2.9 times and 0.7 to 6.5 times. The effect of Mn ~ (2+) on the growth and production of three extracellular enzymes of StEcc-12 was similar to Ca ~ (2+). Ni 2+ significantly inhibited bacterial growth, but the activity of three extracellular enzymes in Ni 2+ -containing culture was 1.7 times higher than that of the control. Enzyme crude extract were added to the three kinds of ions on the activity of PL were inhibited. Zn 2+ had no significant effect on bacterial growth and high concentration of Al 3+ inhibited the growth of bacteria. Both of these ions promoted the production of three extracellular enzymes. With the increase of Fe 2+ concentration and K + concentration, the growth of bacteria decreased, the yield of two pectinase decreased, the yield of protease increased, and the activity of PL enzyme in crude extract decreased. Mg 2+ had no significant effect on bacterial growth and extracellular PG production. Increasing Mg 2+ concentration was beneficial to the production of PL. Enzyme crude extract by adding Mg ~ (2+) PL activity increased. All of the above ions can cause polygalacturonic acid to agglomerate to some extent, but only the effective concentration of Ca 2+ and Mg 2+ is close to the actual concentration of potato tuber.