Investigation of lipid production characteristics of Labyrinthulea capable of growing under an acidic condition and its application for utilization of excess sludge

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K00587
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental engineering and reduction of environmental burden
• Research Institution: Hiroshima University
• Principal Investigator: Satoshi Nakai 広島大学, 工学研究科, 教授 (80313295)
• Co-Investigator(Kenkyū-buntansha): 西嶋 渉 広島大学, 環境安全センター, 教授 (20243602)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: ラビリンチュラ類 / 余剰汚泥 / 多価不飽和脂肪酸

Outline of Final Research Achievements

The optimal pH and salinity for lipid production by Aurantiochytrium sp. strain L3W were 7 and 30 psu, respectively; however it produced fatty acids such as docosahexaenoic acid (DHA). The strain L3W could grow in the medium prepared by adding the sludge sample seawater as sole carbon and nitrogen sources, while hydrolysis was necessary as pretreatment for utilization as its substrates. Analysis of the consumption of C & N in the hydrolyzed sludge sample (HSS) showed that the HSS may be better as a nitrogen source rather than a carbon source to cultivate the strain L3W. As the additional carbon source to the HSS, the jam liquid waste generated from a jam factory demonstrated good acceleration of the growth of the strain L3W as glucose. Finally, production of the fatty acids including DHA by the strain L3W was confirmed in the HSS medium, while the carbon source addition such as the jam liquid waste greatly enhanced its fatty acids production.

Free Research Field

環境化学工学

Academic Significance and Societal Importance of the Research Achievements

本研究では下水処理場から発生する余剰汚泥の有効利用のため、DHAといった有用な脂肪酸を生成する微生物Aurantiochytrium sp. strain L3Wについて、余剰汚泥を利用した培養可能性を敢闘した。その結果、加水分解等の前処理は必要であるが、余剰汚泥を利用した同株の培養、脂肪酸の生成は可能であることを見出した。本成果は、今後の余剰汚泥の利用促進の一助となることが期待される。