Nanotechnology, Food Security and Water Treatment

Nanotechnology is revolutionizing development in almost all technological sectors, with applications in building materials, electronics, cosmetics, pharmaceuticals, food processing, food quality control and medicine. In particular, nano-based sensors use nanomaterials either as sensing material directly or as associated materials to detect specific molecular interactions occurring at the nano scale. Nano biosensors are used for clinical diagnostics, environmental monitoring, food and quality control. Nano biosensors can achieve on site, in situ and online measurements.

The development of science and technology has not only improved the comfort of humans but also added a wide variety of hazardous chemicals and life threatening pathogens into the living environment. Surveillance of bacterial pathogens is a daunting task for healthcare industries, food industries and environmental quality control sectors. During the past few decades, pathogens with high virulence have emerged, leading to steady increase in the mortality and morbidity rates, posing burden on the nation’s economy. Therefore it becomes necessary to develop devices that can quickly sense pathogens in quantities much lower than pico- and femto-moles. A ideal sensor has short sensing time, low measurable quantities and reliable results.

In this chapter we discuss various types of biosensors for pathogen detection. Optical biosensors have been explored extensively and used as labeled (fluorophores, quantum dots, carbon dots), label free (surface plasmon resonance) and hybrid biosensors for a highly sensitive pathogen detection. Piezoelectric-cantilever biosensors are simple, rapid and as effective as conventional pathogen detection techniques and are notable for detection of food pathogens like Listeria monocytogenes. Successful electrochemical biosensors have also been developed with unmodified electrodes and later electrodes were modified with bio-recognition elements such as specific DNA, antibodies or nanoparticles, for detection of pathogens like methicillin resistant Staphylococcus aureus and Salmonella. Almost all biosensors, including immunosensors, are being improved, by sample enrichment or signal amplification, in order to obtain a simple and rapid pathogen detection tool with lower limits of detection.

Nanotechnology delivers emerging applications in functional food by engineering biological and synthetic molecules toward functions that are exceptionally changed from those they have originally. Nanotechnology has enhanced the superiority of foods by making them flavoured, nutritive and more healthier. Nanotechnology generates also novel food products, better packaging, coating and shelf storage techniques. Applications in food also improve shelf life, food quality, safety and fortification. Biosensors in food packaging are designed to detect contaminated or spoiled food. Nanotechnology improve food processes that use enzymes to confer nutrition and health benefits. This report reviews applications of nanotechnology in agriculture, and food science and technology. Furthermore, risk assessment, safety concerns and social implications are discussed.

The global agriculture is facing many challenges including sustainable use and conservation of natural resources, climate change, urbanization, and pollution resulting from agrochemicals (e.g., fertilizers and pesticides). So, the sustainable agriculture is an urgent issue and hence the suitable agro-technological interventions are essential (e.g., nano- and bio-technology) for ensuring the safety and sustainability of relevant production system. Biotechnology and nanotechnology also can be considered emerging solutions to resolve the global food crisis. Nanoparticles or nanomaterials can be used in delivering different nutrients for plant growth. These nanoparticles as nanofertilizers have positive and negative effects on soils, soil-biota and plants. These effects mainly depend on multiple factors including nanofertilizer properties, plant species, soil fate and dynamics as well as soil microbial communities. Nanofertilizers could improve the nutrient use efficiencies through releasing of nutrients slowly and steadily for more than 30 days as well as reducing the loss of nutrients in agroecosystems and sustaining farm productivity. Here we review the plant nano-nutrition including the response of plants and soils to nanonutrients and their fate, dynamic, bioavailability, phytotoxicity, etc. Concerning the effects of nanonutrients on terrestrial environments are still an ongoing processes and it demands further researches as well as a knowledge gap towards different changes in shape, texture, color, taste and nutritional aspects on nanonutrients exposed plants as a major component in the food chain. Moreover, the interaction between nanonutrients and plants, soils, soil biota and the entire agroecosystem will be also highlighted.

The fast growth of nanotechnology has resulted in the production and use of engineered nanoparticles with unique physical and chemical properties in various fields. The increased utilization of engineered nanoparticles enhances the risks associated with their release into the environment. The smaller size and modified physico-chemical properties raise concerns about their entry and adverse effects in plants. For instance, studies have shown that nanomaterials can be absorbed and translocated within plants. Since plants represent a major component of the ecosystem, the accumulation of engineered nanoparticles in plants is a threat to plants and the food chain.

A wide variety of methods are used for water treatment and purification. The use of membranes allows efficient treatment by reverse osmosis, nanofiltration, ultrafiltration, microfiltration, membrane distillation and forward osmosis. Membrane technology has been researched extensively for water treatment and desalination. Desalination is the technology predominantly used to solve water scarcity. The sustainability of desalination processes aims at reducing energy costs and increasing water recovery. In recent years numerous large-scale seawater desalination plants have been built in water-stressed countries. Construction of new desalination plants with the latest emerging technology is expected to increase in the future. Despite major advances in desalination technologies, seawater desalination is still more energy intensive compared to conventional processes uszd for the treatment of fresh water. However, forward osmosis and membrane distillation are emerging for sustainable desalination.

In this chapter we review key points of membrane processes including advantages and disadvantages of forward osmosis and membrane distillation. The advances in membrane material and modules is also discussed elaborately. Drawbacks of forward osmosis are also highlighted within each part, including draw solution development, reverse solute diffusion, concentration polarisation and membrane fouling. This chapter discuss the capability of membrane distillation in treating highly concentrated aqueous solutions derived from other desalination processes. We review the fabrication and performance of membranes, and the optimization of membrane distillation. Finally, the sustainability and application of forward osmosis and membrane distillation in seawater desalination is elaborately analysed.

Heavy metal pollution, cleaning and recycling are a major environmental issue. In particular, there is a need for efficient techniques to treat wastewaters. Conventional technologies to treat industrial waters are limited by stringent health policies and emerging contaminants. Fungi-based nanotechnology is rapidly emerging as an effective technology to treat industrial wastewaters. This chapter reviews the recent developments in fungal biosorption, biological synthesis of nanoparticles using fungi, and the application of fungi-based nanosorbents for heavy metals removal.

Treated wastewater is a reliable water resource for agriculture in arid and semiarid areas. Nanomaterials are promising to clean wastewater. Here we review nanomaterials characteristics, reactivity and potentiality to reduce or remove pollutants from wastewater. Characteristics include high reactivity of surface areas, quantum confinement effects, surface charge density and stability of nanophases. We discuss applications to remove from inorganic and organic contaminants, with focus on reaction kinetics, sorption and degradation. Remediation efficiency is also controlled by wastewater properties such as pH, ionic strength and water temperature.

The use of nanomaterials often allow a removal of more than 80% of most pollutants. Nonetheless, this review explains that the cost, the aggregate formation and the difficulty of recovering most applied nanomaterials are challenging. Alternatively, natural nanomaterials such as nano clay represent an inexpensive and environmental friendly substance for wastewater remediation.

Human activities and industrial processes have led to worldwide heavy metal pollution. Several strategies have been developped for metal remediation. The conventional strategies are expensive, usually low in efficiency and may alter the soil nature. Here we review bioremediation using plants, microbes, e.g. bacteria, fungi, and actinobacteria, earthworms, and algae for metal removal. Bioaugmentation of microbes using plants, earthworms and algae is used to enhance the bioremediation efficiency. We discuss the importance of metagenomics, metabolomics and proteomics approach to assess the response of the living organisms under stress and how they can contribute to the improvement of the already existing strategies.

Continuous exposure of living organisms to toxic compounds is a major health issue. Studying the effects of toxic compounds is a difficult task because compounds are present at trace levels in complex media with other toxic compounds. Toxicity evaluation by animal testing is long and costly. Therefore, this chapter reviews an alternative method of toxicity evaluation, named quantitative structure-activity relationship (QSAR) modelling, which is used to predict the acute toxicity of substances. The principle is that the molecular structure is correlated with toxicological effects. The characteristics of toxic compounds are computed and correlated using software tools and databases. Biodegradation features and classification methods are discussed. Various computational tools and databases are presented. This review also presents the discipline of bionformatics, to study risk, toxicity and biodegradability.