Multidirectional valorization of indigenous Bao rice straw through physicochemical and agronomic conversion pathways for a circular economy
Description
The dataset contains SEM images, FTIR data, EDX data, Raw data in excel, Graphical abstract, rice straw valorization landscape, Zero-waste biorefinery scheme for bioethanol production from rice straw, Sequential stages in the alkaline pretreatment of rice straw for substrate preparation, Stages of rice straw during the entire valorization process, SEM images of untreated rice straw, Graph comparing Weight% and Atomic% of elements, Graph showing Weight% and Atomic% of elements in Biochar of bao rice straw (BRS), Stacked FTIR transmittance spectra of untreated rice straw and straw undergoing various pretreatments with H2SO4, NaOH, STEX and pyrolysis (Biochar), HPLC–RID chromatograms of the fermented hydrolysates, each showing the ethanol peak, Ethanol concentration (%) produced from BRS under different pretreatments. Graphs showing cultivation of microgreens on the damp pretreated rice straw substrate, showing the progression from sowing through germination, growth phase and harvest maturity to a product fit for consumption, Circular-economy scheme for the multidirectional valorization of BRS, Table, Figures, image file, pdf file.
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Steps to reproduce
Bao rice straw (BRS) was collected from rice fields at Ghilamora, Lakhimpur district (27.31°N, 94.41°E), Assam, India. The straw was washed, sun-dried for 6 h, chopped into ~1 cm pieces, oven-dried at 105 °C for 24 h, and stored at room temperature. A portion was ground and soaked overnight in water at a 1:10 (w/v) ratio. Ground BRS was subjected to three pretreatments: steam explosion (15 psi, 121 °C, 1 h), 3% (w/w) H₂SO₄ (121 °C, 30 min), and 3% (w/w) NaOH (121 °C, 30 min). Untreated and pretreated samples were characterized for cellulose, hemicellulose and lignin. Surface morphology and elemental composition were examined using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX), while functional groups were analysed by Fourier-transform infrared spectroscopy (FTIR). For enzymatic hydrolysis, 0.05 M sodium citrate buffer (pH 4.8) was prepared and mixed with rice straw, followed by autoclaving. Cellulase C2730 was added, and hydrolysis was conducted under anaerobic conditions at 50 °C for 72 h in a shaking incubator at 150 rpm. The hydrolysate was separated from residual biomass by filtration. For fermentation, commercial active dry yeast (Saccharomyces cerevisiae) was activated in sterilized distilled water at 33 °C for 30 min. The activated yeast was inoculated into the hydrolysate within 45 min and incubated at 30 °C for 72 h at 150 rpm. The fermented hydrolysate was subsequently filtered. Ethanol was recovered by fractional distillation at approximately 78 °C. Ethanol concentration was quantified by HPLC using a refractive index detector and a Sugar HiPlex Pro analytical column. Quantification was performed using a five-point external calibration curve (1–20%, v/v). For microgreen production, partially dried NaOH-pretreated straw was washed, neutralized and packed into food-grade plastic containers as a 3 cm substrate bed. Spinach (Spinacia oleracea), mustard (Brassica juncea) and bean (Phaseolus vulgaris) seeds were evenly sown on separate beds. Containers were covered with aluminium foil, maintained in darkness and watered twice daily. Microgreens were harvested on day 12. Biochar was produced from residual rice straw by slow pyrolysis at 450 °C in a muffle furnace under anaerobic conditions. Biochar morphology, elemental composition and functional groups were characterized using SEM–EDX and FTIR. Experimental data were recorded in Microsoft Excel, graphs were prepared from the recorded data, and statistical analyses were performed using SPSS version 18.0.
Institutions
- North Lakhimpur UniversityAssam, North Lakhimpur