水分活度对黑根霉生长的影响

Effect of Water Activity on Growth of Rhizopus Nigricans

目的 探讨不同调节剂作用下黑根霉的最低生长水分活度(Aw),以及对其生长的影响。方法 以氯化钠、甘油、蔗糖为调节剂,配制系列Aw不同的沙氏葡萄糖琼脂培养基,将黑根霉菌落转移至培养基上,22.5℃温度下培养21 d,每天测量菌落直径,观察菌落变化。结果 氯化钠组Aw <0.93时,黑根霉无生长迹象;甘油组Aw <0.87时,黑根霉无生长迹象,Aw <0.89时不能产孢;蔗糖组Aw <0.86时,黑根霉无生长迹象,Aw <0.88时不能产孢。随着Aw的降低,黑根霉开始生长时间、产孢时间均推迟,黑根霉的生长速率下降。结论 黑根霉在不同调节剂作用下最低生长Aw分别为0.93(氯化钠)、0.87(甘油)、0.86(蔗糖)。不同调节剂种类对黑根霉最低生长Aw有较大影响。

Objective To investigate the minimum water activity(Aw)required to support the growth of Rhizopus nigricans under the different regulators,and the effect of which on its growth.Methods The sodium chloride,glycerin and sucrose were used as the regulators to prepare a series of Sabouraud dextrose agar(SDA)medium with the different Aw.The colonies of Rhizopus nigricans were inoculated on the SDA medium and cultured at 22.5℃for 21 d.The diameters of colonies were measured and the changes of colonies were observed every day.Results In the sodium chloride group,Rhizopus nigricans could not grow when the Aw<0.93.In the glycerin group,Rhizopus nigricans could not grow when the Aw<0.87,and it could not sporulate when the Aw<0.89.In the sucrose group,Rhizopus nigricans could not grow when the Aw<0.86,and it could not sporulate when the Aw<0.88.With the decrease of Aw,the beginning growth time and sporulation time of Rhizopus nigricans all delayed,and the growth rate of Rhizopus nigricans decreased.Conclusion The minimum Aw required to support the growth of Rhizopus nigricans under the different regulators is 0.93(sodium chloride),0.87(glycerin),0.86(sucrose),and the different types of regulators have a great influence on the minimum Aw required to support the growth of Rhizopus nigricans.