Valorization of agricultural wastes for biofuel applications

Super flexible, self-healing, and self-adhesive double network hydrogel reinforced by okara cellulose nanofibrils

Inspired by the mussel, tannic acid (TA) was modified onto the surface of self-made cellulose nanofibrils (CNFs) to prepare TA@CNFs, which was introduced into borax crosslinked polyvinyl alcohol (PVA) to prepare PTC double-network hydrogel with self-healing properties. Through the comparative observation of TEM images and infrared spectra before and after tannic acid modification, the formation of TA@CNFs was proved. The introduction of TA@CNFs greatly increases the fracture stress of PTC hydrogel, which is more than 10 times higher than that of PVA hydrogel without TA@CNFs, and has high fracture strain (1723 %). Moreover, PTC hydrogel has the ability of rapid self-healing, which can heal to the original form within two minutes. In addition, the temperature response ability of PTC hydrogel makes it capable of reshaping. The self-adhesion ability of PTC hydrogel enables it to adhere to the human epidermis to detect motion signals, as sensitive and as stable as a flexible sensor.

Properties and applications of α-galactosidase in agricultural waste processing and secondary agricultural process industries

Agriculture products form the foundation building blocks of our daily lives. Although they have been claimed to be renewable resources with a low carbon footprint, the agricultural community is constantly challenged to overcome two post-harvest bottlenecks: first, farm bio-waste, a substantial economic and environmental burden to the farming sector, and second, an inefficient agricultural processing sector, plagued by the need for significant energy input to generate the products. Both these sectors require extensive processing technologies that are demanding in their energy requirements and expensive. To address these issues, an enzyme(s)-based green chemistry is available to break down complex structures into bio-degradable compounds that source alternate energy with valuable by-products and co-products. α-Galactosidase is a widespread class of glycoside hydroxylases that hydrolyzes α-galactosyl moieties in simple and complex oligo and polysaccharides, glycolipids, and glycoproteins. As a result of its growing importance, in this review we discuss the source of the enzyme, production and purification systems, and enzyme properties. We also elaborate on the enzyme's potential in agricultural bio-waste management, secondary agricultural industries like sugar refining, soymilk derivatives, food and confectionery, and animal feed processing. Insight into this vital enzyme will provide new avenues for less expensive green chemistry-based secondary agricultural processing and agricultural sustainability. © 2023 Society of Chemical Industry.

Study on the auxin-like activity of organic compounds extracted from corn waste hydrochar prepared by hydrothermal carbonization

This work studied the auxin-like activity of liquid and solid hydrochar from aboveground corn biomass prepared using hydrothermal carbonization (HTC). Understanding the action of organic compounds in regulating plant metabolism is important to develop strategies to improve plant growth and production. Bioassays were performed by testing liquid hydrochar concentrations in the range of 0.0557-5570.0 mg carbon L-1; and solid hydrochar (via extracted dissolved organic matter, DOM) in the range of 0.026-2600.0 mg carbon L-1, using seeds of Lactuca sativa. SEM, ATR-FTIR, and Py-GC/MS were applied to assess the effect of HTC on hydrochar production/composition. Liquid hydrochar presented an intense bioactivity, completely inhibiting the germination of testing seeds at higher concentrations. Liquid hydrochar also was considerably more bioactive. Py-GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids (linear and aromatic) and amino acids. The concentration of more bioactive molecules, rather than their simple presence in the hydrochar fraction, determined the bio-stimulating effect, besides an excellent linear regression between the auxin-like effect and the concentration of active molecules.

Hydrothermal Liquefaction: How the Holistic Approach by Nature Will Help Solve the Environmental Conundrum

Hydrothermal liquefaction (HTL) represents a beacon of scientific innovation, which unlocks nature's alchemical wonders while reshaping the waste-to-energy platform. This transformative technology offers sustainable solutions for converting a variety of waste materials to valuable energy products and chemicals-thus addressing environmental concerns, inefficiencies, and high costs associated with conventional waste-management practices. By operating under high temperature and pressure conditions, HTL efficiently reduces waste volume, mitigates harmful pollutant release, and extracts valuable energy from organic waste materials. This comprehensive review delves into the intricacies of the HTL process and explores its applications. Key process parameters, diverse feedstocks, various reactor designs, and recent advancements in HTL technology are thoroughly discussed. Diverse applications of HTL products are examined, and their economic viability toward integration in the market is assessed. Knowledge gaps and opportunities for further exploration are accordingly identified, with a focus on optimizing and scaling up the HTL process for commercial applications. In conclusion, HTL holds great promise as a sustainable technology for waste management, chemical synthesis, and energy production, thus making a significant contribution to a more sustainable future. Its potential to foster a circular economy and its versatility in producing valuable products underscore its transformative role in shaping a more sustainable world.

Control the carcinogenic bacteria with new polysaccharides from agricultural wastes

Agriculture activities industries produce a huge amount of waste every year. Agricultural wastes are a great source of natural polysaccharides characterized by accessibility, biocompatibility, and ease of modification. Finding new safe antibacterial agents has become one of the top priorities of health organizations worldwide. This priority emerged from the antibiotic resistance pathogenic bacteria hazard. Carcinogenic bacteria are one of the most dangerous antibiotic-resistant pathogenic bacteria. This study tries to investigate the antibacterial activity of polysaccharides from some agricultural wastes against carcinogenic bacteria related to gastrointestinal cancers. We determined the antibacterial activity (in terms of minimum inhibitory concentration (MIC)) and the biofilm reduction capacity. We studied the mechanism of the antibacterial activity by determining the effect of the MIC of the extracted polysaccharides on the plasma membrane permeability and the bacterial DNA content. All extracted polysaccharides showed effective antibacterial activity with low MICs ranging from 2 to 20 μg/mL. The barely straw polysaccharides showed the highest MIC (19.844 μg/mL) against Bacteroides fragilis, while the grape bagasse showed the lowest MIC (2.489 μg/mL) against Helicobacter pylori. The extracted polysaccharide showed high antibiofilm activity. Their capacity to reduce the formation of the pathogenic biofilm ranged from 75 to 95%. Regarding the antibacterial mechanism, the extracted polysaccharides showed destructive action on the DNA and the plasma membrane permeability. The bacterial DNA change percent after the treatment with the different polysaccharides ranged from 29% to -58%. The plasma membrane permeability increased by a high percentage, ranging from 92% to 123%. Agricultural waste polysaccharides are a promising antibacterial agent against antibiotic-resistant carcinogenic bacteria.

Microalgal Feedstock for Biofuel Production: Recent Advances, Challenges, and Future Perspective

Globally, nations are trying to address environmental issues such as global warming and climate change, along with the burden of declining fossil fuel reserves. Furthermore, countries aim to reach zero carbon emissions within the existing and rising global energy crisis. Therefore, bio-based alternative sustainable feedstocks are being explored for producing bioenergy. One such renewable energy resource is microalgae; these are photosynthetic microorganisms that grow on non-arable land, in extreme climatic conditions, and have the ability to thrive even in sea and wastewater. Microalgae have high photosynthetic efficiencies and biomass productivity compared to other terrestrial plants. Whole microalgae biomass or their extracted metabolites can be converted to various biofuels such as bioethanol, biodiesel, biocrude oil, pyrolytic bio-oil, biomethane, biohydrogen, and bio jet fuel. However, several challenges still exist before faster and broader commercial application of microalgae as a sustainable bioenergy feedstock for biofuel production. Selection of appropriate microalgal strains, development of biomass pre-concentrating techniques, and utilization of wet microalgal biomass for biofuel production, coupled with an integrated biorefinery approach for producing value-added products, could improve the environmental sustainability and economic viability of microalgal biofuel. This article will review the current status of research on microalgal biofuels and their future perspective.