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草业学报 ›› 2022, Vol. 31 ›› Issue (5): 103-114.DOI: 10.11686/cyxb2021358

• 研究论文 • 上一篇    

青藏高原燕麦附着耐低温乳酸菌的筛选与鉴定

蔺豆豆(), 琚泽亮, 柴继宽, 赵桂琴()   

  1. 甘肃农业大学草业学院,草业生态系统教育部重点实验室,中-美草地畜牧业可持续发展研究中心,甘肃 兰州 730070
  • 收稿日期:2021-09-27 修回日期:2021-10-31 出版日期:2022-05-20 发布日期:2022-03-30
  • 通讯作者: 赵桂琴
  • 作者简介:Corresponding author. E-mail: zhaogq@gsau.edu.cn
    蔺豆豆(1995-),女,甘肃敦煌人,在读硕士。E-mail: 1843118097@qq.com
  • 基金资助:
    国家自然科学基金(32160810);财政部和农业农村部国家现代农业产业技术体系(CARS-07-C-1)

Screening and identification of low temperature tolerant lactic acid bacterial epiphytes from oats on the Qinghai-Tibetan Plateau

Dou-dou LIN(), Ze-liang JU, Ji-kuan CHAI, Gui-qin ZHAO()   

  1. College of Pratacultural Science,Gansu Agricultural University,Key Laboratory of Grassland Ecosystem,Ministry of Education,Sino-U. S. Centers for Grazing Land Ecosystem Sustainability,Lanzhou 730070,China
  • Received:2021-09-27 Revised:2021-10-31 Online:2022-05-20 Published:2022-03-30
  • Contact: Gui-qin ZHAO

摘要:

为筛选出能改善燕麦低温青贮发酵品质的潜力乳酸菌菌株,对青藏高原不同海拔地区种植的燕麦表面附着乳酸菌资源进行了采集,通过限制性培养方法筛选耐低温菌株,对其耐酸性和耐盐性、产酸速率和生长速度进行分析比较,并用16S rDNA序列分析方法进行了鉴定。结果表明:从不同海拔地区的燕麦植株上初步分离到232株乳酸菌,经进一步革兰氏染色、镜检观察和过氧化氢酶试验筛选,获得56株菌株,对其进行低温筛选,共得到18株耐低温乳酸菌资源,均能在5~20 ℃、3.0%和6.0% NaCl以及pH为3.0~5.0条件下生长,其中14株为同型发酵乳酸菌,4株为异型发酵乳酸菌。14株同型发酵乳酸菌中,OCPP3、OL3、OL8、OL25、OL36、OL54、OL77和OL122的产酸和生长速率较高,3株(OCPP3、OL36和OL77)为戊糖片球菌,2株(OL3和OL54)为戊糖乳杆菌,3株(OL8、OL25和OL122)为植物乳杆菌。在培养25 h后,菌株OL77的OD值在所有培养菌株中最高(2.52),其次为OL54(2.50)。从耐低温、产酸速率和生长速率及多样性角度综合考虑,戊糖片球菌OL77、戊糖乳杆菌OL54和植物乳杆菌OL122适宜作为青藏高原地区燕麦低温青贮的备选添加菌株。

关键词: 青藏高原, 燕麦, 青贮, 耐低温乳酸菌

Abstract:

This research aimed to identify potential lactic acid bacteria (LAB) strains that provide improved fermentation quality of oat (Avena sativa) silage under low temperature. Epiphytic LAB were collected from oat plants at different altitudes on the Qinghai-Tibetan Plateau. Cold tolerant strains were screened by restricted culture, and their acid and salinity tolerance, acid production and growth rate were compared. These strains were identified by means of 16S rDNA sequence analysis. In the initial isolation 232 strains of lactic acid bacteria were isolated, and 56 of these were retained for further screening after Gram’s stain testing, microscopy and a catalase test. Low temperature screening revealed 18 low-temperature tolerant strains. These could grow at temperatures of 5-20 ℃, 3.0% and 6.0% NaCl, and pH 3.0-5.0. Among these 18 strains, 14 were homofermentative and 4 strains were heterofermentative. For the 14 homofermentative LAB strains, strains designated OCPP3, OL3, OL8, OL25, OL36, OL54, OL77 and OL122 had higher acid production and growth rate than others. OCPP3, OL36 and OL77 were identified as Pediococcus pentosaceus, OL3 and OL54 as Lactobacillus pentosus, and OL8, OL25 and OL122 as Lactobacillus plantarum. After culturing for 25 h, the optical density (OD) value of strain OL77 (2.52) was the highest among all cultured strains, followed by OL54 (2.50). Considering the observed low temperature tolerance, acid production and growth rate, and their diversity, these three LAB strains show promise as potential additives for oat silage fermentation at low temperature on the Qinghai-Tibetan Plateau.

Key words: Qinghai-Tibetan Plateau, oats, silage, low temperature tolerant-lactic acid bacteria