Nano-enabled seed treatment: A new and sustainable approach to engineering climate-resilient crops

Under a changing climate, keeping the food supply steady for an ever-increasing population will require crop plants adapted to environmental fluctuations. Genetic engineering and genome-editing approaches have been used for developing climate-resilient crops. However, genetically modified crops have yet to be widely accepted, especially for small-scale farmers in low-income countries and some societies. Nano-priming (seed exposure to nanoparticles, NPs) has appeared as an alternative to the abovementioned techniques. This technique improves seed germination speed, promotes seedlings' vigor, and enhances plant tolerance to adverse conditions such as drought, salinity, temperature, and flooding, which may occur under extreme weather conditions. Moreover, nano-enabled seed treatment can increase the disease resistance of crops by boosting immunity, which will reduce the use of pesticides. This unsophisticated, farmer-available, cost-effective, and environment-friendly seed treatment approach may help crop plants fight climate change challenges. This review discusses the previous information about nano-enabled seed treatment for enhancing plant tolerance to abiotic stresses and increasing disease resistance. Current knowledge about the mechanisms underlying nanomaterial-seed interactions is discussed. To conclude, the review includes research questions to address before this technique reaches its full potential.

Efficient binding paradigm of protein and polysaccharide: Preparation of isolated soy protein-chitosan quaternary ammonium salt complex system and exploration of its emulsification potential

Soy protein isolate (SPI) has good emulsifying ability, but is greatly affected by the environment. The addition of polysaccharides either increases or decreases the stability of SPI. We report and prepared for the first time SPI/HACC complexes with different polysaccharide contents (SPI/HACC ratios are 1:1, 2:1 and 5:1). The binding properties, microstructure and emulsifying properties of the SPI/HACC complexes were determined and analyzed. The results showed that the interaction them is mainly through hydrogen bonding, electrostatic interaction, hydrophobic interaction and steric hindrance effect. The combination of SPI and HACC overcomes their respective limitations and the microstructure is more flat and smooth. It was also found that the emulsifying ability and concentration of SPI showed a certain correlation and the addition of HACC significantly improved the emulsifying ability and storage stability of SPI. This study shows that the prepared SPI/HACC complex has great potential for application in the food industry.

Public understanding of sustainable diets and changes towards sustainability: A qualitative study in a UK population sample

Dietary consumption contributes significantly to the environmental impacts of daily life. Changes to consumption are required, but limited work investigates the reasoning underlying relevant dietary choices. This study aimed to explore public understanding of sustainable diets and any willingness or attempts to make changes towards sustainability in a sample of the UK population. A qualitative approach was used. Twenty-one participants (10 males; predominantly young adults; with a range of living circumstances and cooking responsibilities) were interviewed. Interviews were analysed using inductive thematic analysis. Four themes were identified that related to understanding sustainable diets: 'Consistent with the definition by the Food and Agriculture Organisation of the United Nations (FAO)', 'Multiple benefits', 'Unsure' and 'Competing Interests'. Four themes related to making changes: 'Willing, but unsure', 'Small easy changes', 'Enablers' and 'Barriers'. An additional theme 'COVID-19 pandemic' reflected the period when the work was done (February-May 2021). Within these themes, participants were able to define sustainable eating in a manner that was consistent with and incorporated aspects of the definition by the FAO, could identify sustainable actions that they were undertaking or could undertake, and considered these to be beneficial, but there was a lot of uncertainty, and alternative or competing definitions and actions were also given. Participants were also willing to make changes to make their diet more sustainable, and preferences were expressed for small easy changes of high impact, but there was again considerable uncertainty as to what changes to make. Caution due to the small and select sample is required, but suggestions from this work include increasing awareness and knowledge of the environmental impacts of dietary choices, focusing on small easy changes of likely impact and personal benefit, and increasing availability and accessibility to sustainable diets.

Hydrophobic and dispersible Cu(I) desulfurization adsorbent prepared from Pistia stratiotes for efficient desulfurization

Improving the adsorption capacity of adsorbents is a good way to boost their desulfurization efficiency. Optimizing the dispersion of metal nanoparticles and enhancing the stability of the metal valence state are essential to maximizing the adsorption capacity of the metal-loaded desulfurization adsorbent. Pistia stratiotes can absorb the Cu in water and evenly disperse it throughout the plant, allowing the production of a highly dispersed Cu(I) adsorbent (PSAC-Cu(I)). During the usage and storage of PSAC-Cu(I), Cu(I) oxidizes to Cu(II) when it comes in contact with oxygen and water, reducing its adsorptive capacity; hence, we modified PSAC-Cu(I) hydrophobically using polydimethylsiloxane (PDMS) to generate PSAC-Cu(I)-P(200). The outcome of the two-month exposure experiments showed that only 4.7% of the Cu(I) of PSAC-Cu(I)-P(200) was oxidized in the humid atmosphere, whereas PSAC-Cu(I) was almost fully oxidized. Moreover, the dibenzothiophene adsorption capacity of PSAC-Cu(I)-P(200) in a model oil with a water concentration of 250 ppmw is 68 mg g^-1, which is 1.62 times that of PSAC-Cu(I). When 10 wt% toluene was added to the model oil, the adsorption desulfurization capacity of PSAC-Cu(I)-P(200) decreased to 86.8% of the original. This shows that PSAC-Cu(I)-P(200) has good stability and excellent adsorptive desulfurization performance.

Fungal bioleaching of WPCBs using Aspergillus niger: Observation, optimization and kinetics

In this study, Aspergillus niger (A. niger) as an environmentally friendly agent for fungal bioleaching of waste printed circuit boards (WPCBs) was employed. D-optimal response surface methodology (RSM) was utilized for optimization of the bioleaching parameters including bioleaching method (one step, two step and spent medium) and pulp densities (0.5 g L^-1 to 20 g L^-1) to maximize the recovery of Zn, Ni and Cu from WPCBs. According to the high performance liquid chromatography analysis, citric, oxalic, malic and gluconic acids were the most abundant organic acids produced by A.niger in 21 days experiments. Maximum recoveries of 98.57% of Zn, 43.95% of Ni and 64.03% of Cu were achieved based on acidolysis and complexolysis dissolution mechanisms of organic acids. Based on the kinetic studies, the rate controlling mechanism for Zn dissolution at one step approach was found to be diffusion through liquid film, while it was found to be mixed control for both two step and spent medium. Furthermore, rate of Cu dissolution which is controlled by diffusion in one step and two step approaches, detected to be controlled by chemical reaction at spent medium. It was shown that for Ni, the rate is controlled by chemical reaction for all the methods studied. Eventually, it was understood that A. niger is capable of leaching 100% of Zn, 80.39% of Ni and 85.88% of Cu in 30 days.

Environmentally-friendly strategy for separation of 1,3-propanediol using biocatalytic conversion

Glycerol waste from the biodiesel production can be used as a carbon source in the production of 1,3-propanediol (1,3-PD) through microbial fermentation. However, downstream processing is a major bottleneck that restricts its biological production. Here, we investigated an environmentally-friendly method to enzymatically separate 1,3-PD. The transformation of 1,3-PD to an ester was achieved by exploiting the esterification reaction with fatty acids under lipase catalysis. The reaction efficiency was optimized using different poly-alcohols that were existed in the fermentation broth reacted with a fatty acid. Whereas the 1,3-PD conversion reached 62%, only a 0.06% and 0.08% conversion was reached for 2,3-butanediol and glycerol, illustrating the former's more efficient separation. The recovery efficiency of 1,3-PD was 96%. Finally, 1,3-PD was obtained by lipase-directed ester hydrolysis. Taken together, the bio-catalyzed separation process presented here is a novel and promising method for recovering 1,3-PD.