|
|
Hokkaido University Collection of Scholarly and Academic Papers >
Theses >
博士 （農学） >
Route exploration of valorization of buckwheat waste based on subcritical liquid treatment
|
Files in This Item:
|
|
|
Related Items in HUSCAP:
|
| Title: | Route exploration of valorization of buckwheat waste based on subcritical liquid treatment |
| Other Titles: | 亜臨界液体処理によるソバ廃材の付加価値化方法に関する検討 |
| Authors: | Yuan, Yongheng Browse this author |
| Issue Date: | 25-Sep-2023 |
| Publisher: | Hokkaido University |
| Abstract: | Buckwheat waste (BWW), which includes husks, leaves, and straw, is usually thrown away or burned. This leads to serious pollution problems and a waste of resources. BWW is rich in cellulose, hemicellulose, antioxidants, and various sugars;thus, it can be considered as a potential source to improve the economic benefits of buckwheat cultivation. However, components such as sugars and antioxidants in BWW are often cross-linked with structural compounds via chemical bonds.
Therefore, it is vital to develop a strategy to facilitate depolymerization of these structures and improve the utilization efficiency of BWW.
In this study, subcritical water has been developed to improve the yields of saccharides from BWW. Subcritical ethanol solution was used to increase the yields of bioactives components. The scale-up to an industrial level was tested on a pilot scale. The hydrolysate prepared from subcritical seawater treatment of BWW has also been tested as a liquid fertilizer to promote lettuce growth.
1. Subcritical water treatment of BWW for sugar extraction A subcritical water treatment (SWT) was chosen for cellulose and hemicellulose degradation to produce saccharides from raw BWW. The sum of saccharides yields in the liquid sample were compared. A higher sum of saccharides yields of 4.10 % was obtained at a relatively lower severity factor of 3.24. The contents of cellulose, hemicellulose, and lignin were analyzed in the residue after SWT. The result shows that lignin was dominant in the residue. The irregular pores were observed by SEM after SWT due to the removal of some hemicellulose, and lignin. Finally, an overall mass conversion based on saccharides production was carried out. The result reflects a considerable yield of saccharides from BWW by SWT.
2. BWW depolymerization using a subcritical ethanol solution for extraction of bioactive components: from the laboratory to pilot scale Subcritical ethanol solution treatment (SEST) was used to depolymerize BWW and extract bioactive components such as phenolics, flavonoids, and sugars on both the laboratory and the pilot scale. On the laboratory scale, various treatment conditions were compared. Depolymerization of the microstructure was evaluated by the detection of solid components, and the extraction of bioactive compounds was studied by the detection of liquid components. The mechanism of SEST depolymerization of BWW and the extraction of bioactive components is discussed.
Scaling up to an industrial level was tested on a pilot scale, and solid and liquid components were identified. The total phenolics content increased significantly because SEST promoted the degradation of lignin and the solubilization of extractive components. The yield of total flavonoids did not change significantly with increases in the temperature, which could be attributed to the degradation of some flavonoid components at high temperature. Reducing sugars were present mainly in the form of polysaccharides, which was attributed to the low temperature. The maximum total yields of phenolics, flavonoids, and reducing sugars were 29.8 ± 0.1, 13.9 ± 0.5 and 33.9 ± 0.5 g/kg, respectively. This study provides valuable reference data for BWW utilization on a pilot scale.
3. Effect of hydrolysate from subcritical seawater treatment of BWW as liquid fertilizer on lettuce growth BWW was treated with subcritical seawater treatment (SST) at different treatment temperatures. The collected hydrolysate was used as a liquid fertilizer for lettuce growth, and finally the physico-chemical properties of hydrolysate and the growth indexes of lettuce under each condition were examined. The results showed that after SST of BWW, the salt content decreased while some antioxidants and sugars increased because of the hydrolysate. The hydrolysate was able to promote the growth of lettuce. The maximum weight of lettuce cultivated with the hydrolysate was 22 g, with an average height of 14 cm at 170 ℃ of SST. This study combined the reuse of biomass and seawater for agricultural cultivation, which provided a new way to use BWW, it acts as a reference for the irrigation of seawater in agricultural cultivation,and also increased the added value of buckwheat cultivation. |
| Conffering University: | 北海道大学 |
| Degree Report Number: | 甲第15605号 |
| Degree Level: | 博士 |
| Degree Discipline: | 農学 |
| Examination Committee Members: | (主査) 准教授 清水 直人, 教授 岩渕 和則, 教授 松浦 英幸 |
| Degree Affiliation: | 農学院（農学専攻） |
| Type: | theses (doctoral) |
| URI: | http://hdl.handle.net/2115/90833 |
| Appears in Collections: | 課程博士 (Doctorate by way of Advanced Course) > 農学院(Graduate School of Agriculture)
学位論文 (Theses) > 博士 （農学）
|
|
