Research of microbial metabolisms that function in soil-humic acid homeostasis

2016 Fiscal Year Final Research Report

• Project/Area Number: 26310303
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 特設分野
• Research Field: Food Cycle Research
• Research Institution: University of Tsukuba
• Principal Investigator: TAKAYA Naoki 筑波大学, 生命環境系, 教授 (50282322)
• Project Period (FY): 2014-07-18 – 2017-03-31
• Keywords: フミン酸 / 糸状菌

Outline of Final Research Achievements

Humic acid (HA) is one of the major components of soil humic substance while little is known about interaction between HA and soil microorganisms. This study indicated that tens of filamentous fungi absorb HA, and metabolize HA to high-molecular weight compounds in laboratory-scale cultures. A culture of the model filamentous fungus Aspergillus nidulans, which we found efficiently metabolizes HA, converted HA to more oxidized compounds with higher content of phenol and carboxy moieties. Transcriptome of the fungus cultured in the presence of HA indicated that HA altered global transcription of the fungus. Biochemical studies indicated that HA switched the fungal respiration mechanism to cyanide-resistant one, and stimulated cell growth under the culture conditions. These results presented novel examples of physiological interaction between HA and soil microorganisms, and impacts homeostasis of terrestrial HA that is mediated by natural microorganisms.

Free Research Field

応用微生物学