琼脂糖酶产生菌的筛选和培养基优化

Screening of an Agarase-Producing Strain and Optimization of Culture Medium

摘要:

从太岁中筛选得到一株初始产酶较高的琼脂糖酶产生菌，经形态和分子生物学分析方法鉴定之后，认定其属于类芽孢杆菌属（Paenibacillus ），命名为Paenibacillus sp. P1（简称为P1）。P1为革兰氏阴性菌，短杆状细胞，对明胶和纤维素都没有水解活性。研究该菌的生长及产酶过程发现，该菌株最适发酵产酶时长是40 h。利用单因素实验对发酵培养基进行优化，最终确定了最适合菌株P1产琼脂糖酶的发酵培养基配方为：Agar 3 g/L、蛋白胨2 g/L、K₂HPO₄·3H₂O 1.0 g/L、NaCl 0.3 g/L、MgSO₄·7H₂O 0.05 g/L、FeSO₄·3H₂O 0.02 g/L、CaCl₂ 0.04g/L。菌株P1在优化后的培养基中发酵40 h，琼脂糖酶产量达到了3.47×10⁴ U/L，是优化前产酶水平的3.4倍。实验结果为非海洋来源的产琼脂糖酶菌株筛选和琼脂糖酶的放大发酵奠定了基础。

Abstract:

An agarase-producing strain with high initial enzyme was isolated from Taisui. The strain was identified as Paenibacillus after morphological and molecular biological analysis and named Paenibacillus sp. P1(abbreviated as P1). The strain P1 which had a rod-shaped cell was a Gram-negative bacterium. And it could not hydrolyze gelatin or cellulose. The optimum fermentation time of strain P1 was 40 h based on the study of the growth and enzyme production of strain P1. Single factor experiment was used to optimize the fermentation medium.The optimal medium for agarase production from P1 strain were Agar 3 g/L, peptone 2 g/L,K₂HPO₄·3H₂O 1.0 g/L, NaCl 0.3 g/L, MgSO₄·7H₂O 0.05 g/L, FeSO₄·3H₂O 0.02 g/L, and CaCl₂ 0.04 g/L. The strain P1 was fermented in the optimized medium for 40 h and the agarose activity was 3.47×10⁴ U/L after optimization, which was 3.4 times higher than that before optimization. The results lay a foundation for the screening of agarose-producing strains from non-marine sources and the scale-up fermentation of agarose.