中国农业科学 ›› 2020, Vol. 53 ›› Issue (22): 4683-4690.doi: 10.3864/j.issn.0578-1752.2020.22.014

• 食品科学与工程 • 上一篇    下一篇

pH和缓冲作用对香菇菌丝生长的影响

段应策,胡姿仪,杨帆,李金涛,邬向丽,张瑞颖()   

  1. 中国农业科学院农业资源与农业区划研究所/农业部农业微生物资源收集与保藏重点实验室,北京 100081
  • 收稿日期:2020-04-06 接受日期:2020-09-04 出版日期:2020-11-16 发布日期:2020-11-28
  • 通讯作者: 张瑞颖
  • 作者简介:段应策,Tel:18210633620;E-mail: yingceduan@163.com
  • 基金资助:
    国家食用菌产业技术体系(CARS-20)

Effects of pH and Buffering on the Growth of Lentinula edodes Mycelium

DUAN YingCe,HU ZiYi,YANG Fan,LI JinTao,WU XiangLi,ZHANG RuiYing()   

  1. Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences / Key Laboratory of Agricultural Microbial Resources Collection and Preservation, Ministry of Agriculture, Beijing 100081
  • Received:2020-04-06 Accepted:2020-09-04 Online:2020-11-16 Published:2020-11-28
  • Contact: RuiYing ZHANG

摘要: 背景香菇是我国栽培规模最大的食用菌,随着栽培规模的不断扩大,栽培模式也在发生转变。菌棒的工厂化生产和液体菌种技术开始广泛应用,对栽培原料、生产工艺和培养条件的要求越来越高。pH是决定香菇菌丝生长和菌种质量的一个重要因素,香菇虽然能在pH 3.0—7.0的范围内生长,但香菇生长的最适pH以及培养料中的缓冲系统对菌丝生长的影响机制尚不清楚。【目的】检测香菇菌丝生长的最适pH,并分析培养料中的缓冲系统对菌丝生长的影响,为香菇生产提供理论依据。【方法】在PDA培养基上,利用HCL和NaOH调节pH,分析香菇生长的最适pH;利用GC-MS和HPLC检测木屑尤其是发酵酸化的木屑中有机酸的种类和含量,在PDA培养基上分别检测有机酸、有机酸钙及其缓冲液对香菇菌丝生长速度的影响;通过测定香菇菌丝生长代谢对PDA培养基pH的调节,最终揭示pH和缓冲作用抑制香菇菌丝生长的机制。【结果】香菇能够在pH 3.0—7.0的范围内生长,但生长最适pH为4.0。当培养基pH>4.0时,香菇菌丝生长过程中通过代谢降低培养基的pH,最终降低至4.0,以有利于菌丝的生长。当培养基pH>4.0,并且含有缓冲系统,阻碍香菇对培养基pH的调节时,则抑制香菇菌丝的生长。当缓冲作用达到一定的阈值,可完全抑制菌丝的生长,导致菌种不萌发,如25 mmol?L -1的柠檬酸-柠檬酸钠缓冲液在pH 6.0和7.0时可完全抑制香菇菌丝的萌发。【结论】香菇生长最适pH为4.0,当pH>4.0时,香菇菌丝通过代谢调节培养基pH,缓冲液通过阻碍菌丝对环境pH的调节而抑制菌丝生长。

关键词: 香菇, 有机酸, pH, 缓冲作用, 菌丝生长

Abstract:

【Background】Lentinula edodes, known as Xianggu, is one of the most important commercial edible mushrooms in China. With Xianggu cultivation scale increasing, new technology and process such as liquid spawn were developed, and many factories for artificial logs were built in past several years. The requirements for substrates and culture conditions are more stringent in factory. The pH is one important factor for cultivation of Xianggu, and L. edodes is able to grow at pH 3.0-7.0, but the optimum pH and influence of buffering remained unclear.【Objective】The optimum pH was determined and the effects of buffers in substrates on mycelial growth of L. edodes were evaluated in this study, and the mechanism for inhibition of buffer to mycelia was elucidated.【Method】The optimum pH was investigated according to mycelial growth rate on PDA media, which were adjusted with HCL and NaOH. The organic acids in sawdust especially acidified sawdust were identified with GC-MS and HPLC. The effects of organic acids, calcium salts and the buffers on mycelial growth were researched. The change of media pH during mycelial growing was detected.【Result】The pH for mycelial growth ranged from 3.0 to 7.0, moreover, the optimum pH was 4.0. The mycelia were able to regulate media pH to 4.0 when the primary pH was more than 4.0. The buffer inhibited mycelial growth by impeding adjustment of media pH. When the buffer capacity reached a threshold, the mycelia were inhibited completely. For example, the mycelia were not able to germinate on the PDA media, which contained 25 mmol?L -1 citric acid-sodium citrate buffer of pH 6.0 and pH 7.0.【Conclusion】The optimum pH for mycelial growth was 4.0. The mycelia was able to regulate media pH to 4.0 when the primary pH was more than 4.0. Given that buffering hindered pH changes of media, the mycelia growth would be inhibited.

Key words: Lentinula edodes, organic acid, pH, buffer capacity, mycelial growth