Utilization of biogas digestate for seaweed (nori) cultivation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K12430
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64050:Sound material-cycle social systems-related
• Research Institution: Osaka Prefecture University
• Principal Investigator: Kuroda Kana 大阪府立大学, 人間社会システム科学研究科, 准教授 (70708023)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: メタン発酵残渣 / 色落ちノリ / 栄養塩の偏在 / 海産バイオマス

Outline of Final Research Achievements

The purpose of this study is to find valuable means of digestate by applying the digestate to decolored nori. Laboratory-scale experiments of continuous anaerobic digestion using three biomass (Ulva sp., vegetable and fishery waste) were conducted. The main findings from the continuous anaerobic digestion and nori cultivation with the digestate are as follows. Liquid phase produced from digestate of all the biomass contributed to a quick recovery from decolored conditions. From the safety viewpoints, the concentration of heavy metal (As and Hb) of cultured nori was lower than natural nori, and Cd and Hg were not detected. These results can contribute to a biogas society at proposing a circular economy with a marine viewpoint.

Free Research Field

海洋環境学

Academic Significance and Societal Importance of the Research Achievements

本研究により，メタン発酵残渣を制御・管理し，海域で利用する可能性が具体的に示された。色落ちノリは喫緊の課題であり，メタン発酵残渣により化学肥料の施肥削減につながる。また，栄養塩の偏在の解消につながるとともに，栄養塩の適正管理に向けた新たな活路が見出されたといえる。加えて，メタン発酵残渣の処理が課題の一つであるメタン発酵技術の普及にもつながる。次に，アオサ由来の発酵残渣の特異な特徴を活かすことで，未価値同然の海産バイオマスの付加価値が向上し，未活用海産バイオマスに新たなインパクトを与えるものである。最後に，海を介した物質循環の健全化につながり，海陸一体型物質循環型社会の礎となる。