Utilization of the saccharification residue of rice straw in the preparation of biochar is a novel strategy for reducing CO2 emissions

Jiajun Hu; Hongcheng Guo; Xiahui Wang; Min-Tian Gao; Guodong Yao; Yiu Fai Tsang; Jixiang Li; Jianfang Yan; Saiwei Zhang

doi:10.1016/j.scitotenv.2018.09.099

Utilization of the saccharification residue of rice straw in the preparation of biochar is a novel strategy for reducing CO₂ emissions

Sci Total Environ. 2019 Feb 10;650(Pt 1):1141-1148. doi: 10.1016/j.scitotenv.2018.09.099. Epub 2018 Sep 8.

Authors

Jiajun Hu¹, Hongcheng Guo², Xiahui Wang¹, Min-Tian Gao³, Guodong Yao⁴, Yiu Fai Tsang⁵, Jixiang Li⁶, Jianfang Yan⁷, Saiwei Zhang⁸

Affiliations

¹ Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China.
² Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China; Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
³ Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China. Electronic address: mtgao@shu.edu.cn.
⁴ State Key Lab of Metal Matrix Composites, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
⁵ Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong, China.
⁶ Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
⁷ Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong, China; State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
⁸ State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.

PMID: 30308802
DOI: 10.1016/j.scitotenv.2018.09.099

Abstract

Once rice straw has been bioconverted into biofuels, it is difficult to further biodegrade or decompose the saccharification residue (mainly lignin). Taking into account the pyrolysis characteristics of lignin, in this study the saccharification residue was used as a raw material for the preparation of biochar (biochar-SR), a potential soil amendment. Biochar was prepared directly from rice straw (biochar-O) with a yield of 32.45 g/100 g rice straw, whereas 30.14 g biochar-SR and 30.46 g monosaccharides (including 20.46 g glucose, 9.11 g xylose, and 0.89 g arabinose) were obtained from 100 g of rice straw. When added to liquid soil extracts as a soil amendment, almost nothing was released from biochar-SR, whereas numerous dissolved solids (about 70 mg/L) were released from biochar-O. Adding a mixture of biochar-SR and autotrophic bacteria improved soil total organic carbon 1.8-fold and increased the transcription levels of cbbL and cbbM, which were 4.76 × 10³ and 3.76 × 10⁵ times those of the initial blank, respectively. By analyzing the soil microbial community, it was clear that the above mixture favored the growth of CO₂-fixing bacteria such as Ochrobactrum. Compared with burning rice straw or preparing biochar-O, the preparation of biochar-SR reduced CO₂ emissions by 67.53% or 37.13%, respectively. These results demonstrate that biochar-SR has potential applications in reducing the cost of sustainable energy and addressing environmental issues.

Keywords: Autotrophic bacteria; Biochar; CO(2) fixation; Saccharification residue; Soil.