一株分离自鳜鱼肠道的粘质沙雷氏菌（Serratia marcescens）HFUT 1301的鉴定及灵菌红素的分析

Identification of Prodigiosin-producing Serratia marcescens HFUT1301 Strain Isolated from Mandarin Fish Intestine

摘要:

灵菌红素是粘质沙雷氏菌(Serratia marcescens)产生的具有抗癌功效的一种色素。本研究从鳜鱼肠道中筛选出一株高产红色素的菌株，根据形态学特征、生理生化性质、16S rDNA对其进行鉴定，采用紫外可见光全波长扫描、LC-MS和FT-IR图谱鉴定该菌种产红色素的结构，研究表明：在基础培养基上菌落呈圆形、直径1-3 mm、中间红色不透明，呈隆起状、边缘整齐，16S rDNA片段大小为1445 bp，与粘质沙雷氏菌同源性为99%，将该菌株命名为S.marcescens HFUT 1301；通过超声波辅助乙醇浸提及硅胶色谱分离纯化，获得纯度超过95%的红色素；在pH 3和pH 10的甲醇溶液中，该色素分别在535 nm和470 nm波长处存在明显吸收峰；LC-MS图谱主要离子峰为323.5486和324.8468；FT-IR图谱的主要吸收波数为3396 cm-1、2923 cm-1、2851 cm-1、1710 cm-1、1465 cm-1和1164 cm-1。根据已有报道灵菌红素结构特征，推测该红色素为灵菌红素。在发酵培养基上灵菌红素产量达到3.22 g/L。

Abstract:

Prodigiosin, a pigment with anti-cancer effects, is produced by Serratia marcescens. A strain producing a red pigment was screened from the intestinal canal of mandarin fish and identified on the basis of colony morphology, physiological and biochemical characteristics, and 16S rDNA analysis. The structural characteristics of the red pigment was determined using ultraviolet-visible (UV-Vis) spectrophotometry, liquid chromatography-mass spectrometry (LC-MS), and Fourier transform infrared spectroscopy (FT-IR). The results showed that it appeared round colonies on basic medium, the diameter was within 1 to 3mm, the middle of the colony was red and opaque with a slight bulge in the center, and with smooth edges, while 16S rDNA fragment (1445 bp in size) showed 99% similarity with S. marcescens. This isolated strain was designated as S. marcescens HFUT1301. The purity of the red pigment exceeded 95% after ultrasound-assisted ethanol extraction and silica gel column chromatography. In pH 3- and pH 10-methanol solutions, there were significant absorption peaks at 535 and 470 nm, respectively. LC-MS showed that the main ion peaks were 323.5486 and 324.8468. The main absorption wavenumbers for FT-IR were 3396, 2923, 2851, 1710, 1465, and 1164 cm-1. Red pigment production reached 3.22 g/L in the fermentation medium. Based on previously reported structural characteristic of prodigiosin, the red pigment produced from S. marcescens HFUT1301 was speculated to be prodigiosin.