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The global community is in a quest for nutritional and environment-friendly resources as a part of their food habit. The ubiquitous trend of veganism tied with the increasing apprehensions towards animal welfare, negative impact on human health and the environment has escalated the demand for meat alternatives mainly plant-based meat analogues (PBMA). Protein-rich bioresources such as cereals, vegetables, and algae have been explored to mimic animal meat in a similar flavour, texture, sensory and aromatic properties. This review aims to summarize the recent advancements in functional food technology based on vegetal proteins, a comparative account of traditional and commercially available meat alternates. The literature search for the last 10 years shows the rise in research on plant ingredients to develop novel human foods. A brief account of various production methods and their processing effects to improve the structural and techno-functionality of PBMA is suggested for designing sustainable food. The different combinations of plant and animal proteins are discussed to enhance the nutritional aspect, organoleptic profile and shelf-life of available food products. The positive feedback resulted in booming food industries across the world, incorporating vegetal proteins. The global market trend introducing well-established and promising food brands is listed to discuss the prospects of PBMA.

The current study aimed to investigate the concurrent production of astaxanthin and lipids using Chlorella sorokiniana under mixotrophic conditions in an external loop airlift photobioreactor (ELAPB). Supplementation of Fe2+ into the media in the red phase (stress phase) induced the astaxanthin production. The maximum yield of 154.36 mg L−1 was obtained by the end of the red phase, which is equivalent to 3.4% of the dry biomass weight. The role of reactive oxygen species in the formation of astaxanthin, which protects the microalgal cells from different oxidative stress, has been elucidated. Apart from astaxanthin, unsaturated fatty acids (81.34%) were also produced with excellent biodiesel properties. Unsaturated fatty acids viz., palmitoleic acid (16:1), have resulted in high yields (22.85%), followed by linoleic acid (18:2), 28.27%; oleic acid (C18:1), 14.38%; and eicosapentaenoic acid (20:5), 4.49%. Hence, the simultaneous production of high value-added products, viz., astaxanthin, and lipids makes the whole process economically viable and environmentally sustainable and elevates the commercial potential during scale-up. The astaxanthin radical scavenging activity was also assessed by H2O2 assay, and the maximum scavenging activity was determined as 91%. The study confers the potential advantages of algal cultivation for high-value commercial product synthesis towards additional revenue generation and development of an efficient microalgae-based biorefinery process.

Flavonoids are the secondary metabolites synthesized by microalgae and have diverse applications in various fields. The present study compares among two microalgal strains, Chlorella vulgaris (CV) and Chlorella pyrenoidosa (CP), for the production of flavonoids and lipids, which were cultivated in mixotrophic as well as autotrophic modes. This study also focuses on the role of l-phenylalanine as a supplement to enhance flavonoids. The current work establishes the relation between nitrates, external carbon, and l-phenylalanine for enhanced production of flavonoids and lipids. The extracted flavonoids were found to be maximum in CP-autotrophic mode followed by CV-mixotrophic mode with 138 μg/ml and 118 μg/ml, respectively. The common flavonoids observed with both the microalgal strains were quercetin, catechin, and p-coumaric acid. In comparison, the production of the maximum lipid of 23.7% was reported with mixotrophic operation in CV, followed by CP (19.4%). The scavenging activity of the extracted flavonoids was determined using a hydrogen peroxide assay and was found to be in the range of 63–73% at all experimental conditions. CP was found to produce more flavonoids in autotrophic mode, whereas mixotrophic mode showed maximum production of lipids and flavonoids in the CV. The simultaneous production of high value-added products, viz., flavonoids and lipids, not only paves a pathway for the biorefinery approach but also elevates the commercial potential during scale-up. Graphical abstract

Background: The rapid eruption of Coronavirus at the end of 2019 has caused global health crisis and significant loss to the economy and social well-being. This created a massive shortage of advanced health facilities with inadequate medicinal supply, further deteriorating human health conditions. On the basis of adverse effects of the ongoing pandemic, this review has been proposed to evaluate the antiviral efficacy of plant- based therapeutics, against SARS-CoV-2 (commonly called COVID-19) infection. It highlights the possible action of the mechanism of phytotherapeutic drugs against coronavirus inhibition, further validated by clinical trials on herbal formulas is reviewed. Though the experimental studies on COVID-19 treatment are limited, the undesirable side effects of herbal drugs and unidentified compounds cannot be ignored. Objective: We have made an effort to study the prospective plant-derived bioactive entities and their effectiveness in the treatment of COVID-19 and also emphasize on safety and regulatory concerns of phytomedicines. Methods: The methodology involves relevant studies on COVID-19 treatment based on herbal extracts and the purified bioactive metabolites. The e-literature survey has been done by downloading research articles available on PubMed (National Library of medicine), Elsevier, and Google scholar search engines. The keywords used are plant metabolites, natural bioactive, phytotherapeutic drugs, clinical trials, SARS-CoV-2, Coronavirus inhibitors and herbal extracts. Results: The review pays particular attention to the etiological study of the COVID-19 virus and its inhibition using medicinal plant metabolites as immunomodulatory agents. The application of valuable bioactives like phenolic compounds, saponins, alkaloids, tannins, flavonoids and terpenoids in preparing herbal formula/drug has been focused on. The drug resistance of bioactive compounds and their side effects on human health were discussed for effective phytomedicine, thus, emphasizing the perspectives of phytotherapeutic drugs as a safe remedy to boost immunomodulatory functions and antiviral activity against COVID-19. Conclusion: Altogether, the review presents the action mechanism of plant extracts rich in bioactive compounds and depicted potential antiviral activity against SARS-CoV-2. These plant bioactive compounds can serve as lead molecules to develop phytomedicine, ensuring all safety regulations in the clinical trials to treat or prevent COVID-19 viral infections.

The marine ecosystem is a massive source and home for countless microorganisms, several aquatic animals, and even higher plants and animals for many decades. A mutualistic relationship exists between the marine aquatic species as well as the marine microbes, which are mutually benefitted against each other (both prokaryotic and eukaryotic microbes like bacteria, fungi, viruses, and even marine algae). During their life cycle, these organisms produce several enzymes, which are used in several of the industries for the well-being of humans and other living organisms. A number of enzymes currently available in the market are produced by these microbes in different pathways, possessing a special feature as well as characteristics required by several industries for preparation of materials. Variety of enzymes with special activities have been isolated from marine bacteria, actinomycetes, fungi, and other marine microorganisms by researchers in recent years, and some products already found industrial applications. In this chapter, we shall discuss various pathways/steps applied in the production of enzymes through a greener approach by using several nanotechnologies available in making the enzyme product more viable and even increase the shelf life of the product so that it can be used for a longer period of time, which include various properties of enzymes like thermotolerance, thermos-stability of an enzyme over an extensive temperature and pH range. Also, with existing bioreactors, these microbes can be cultivated and produce enzymes using greener synthesis. The bacterial marine enzymes are used in different industrial applications beneficial to humans as they can withstand harsh conditions. In this work, authors try to limit over application focus mainly on medicine and biotechnology, energy and biofuels, food, nutrition and agriculture, and others. With the sustenance of nanotechnology, increase the stability of enzymes by the application of existing greener approaches were discussed.

Nowadays pollution is a major concern for human mankind. As the generations are passing by, the more the worse it is getting to protect the environment. Every part of the environment is being contaminated due and in reverse, the humans and the other living being getting affected due to the consequences done by humans. Even though there are several technologies available to protect the environment still we find some voids to fill in and in this process, new technology evolves in. Water pollution is also considered to be one of the most ghastly situations, where economic development, rapid industrialization and even the population overgrowth is playing a key role. Due to rapid growth the release of several organic as well as inorganic substances into the environment, this is further leading to environmental pollution as well as the contamination of water. Because of this, combining nanotechnology in wastewater treatment will improve the quality of water. The major advantage of using the nanoparticles is they possess unique characteristics and have a high surface area where the unwanted particles get absorbed in these nanoparticles and get removed from them because of their high surface area. It can also be used for removing toxic substances. In this chapter, we discuss the latest technologies, which are available right now using the chalcogenides nanomaterials. Like, to disinfect the bacterial communities in wastewater, aspects of chalcogenide nanomaterials, as catalysts, remediation of various environmental contaminants, and their role in treating the contaminated water including organic contaminants degradation alongside bacterial disinfection.

Compost is widely used to improve soil fertility for its chemical–physical properties, with particular regard to the abundance of humic substances. Compared to the untreated organic solid waste, the use of compost in microbial fuel cells (MFCs) could offer different advantages like the strong reduction of fermentative processes. The use of compost in MFCs in combination with soil or mixed with other substrates had been reported by some researchers to improve the performance of MFCs fed with agro-industrial residues and plant MFCs. In this chapter, we report the results of an experiment carried out using a compost of vegetable residues as feedstock in a single chamber, air cathode MFCs. We investigated the behavior of two MFCs serially connected, the possibility to use compost as a long-term source of energy in MFCs, the influence of cathode surface/cell volume ratio on MFCs performance in terms of power and current density. Our results showed for MFCs serially connected a maximum PD and CD of 234 mW/m2 and 1.6 A/m2, respectively, with a maximum OCV of 557 mV. Unexpectedly, the compost-based MFCs kept significant electric outputs (854 mV, 467 mW/m2 kg, and 114 mA/m2 kg) after being reactivated 2 years later its set-up, thus demonstrating its potential as long-term operation energy system.

Global industrial operations and commodity productions rely on fossil fuels that are non-renewable resources, projected to be exhausted by 2050. To mitigate and compensate for the high-end use of fossil fuel consumption, the use of renewable energy resources, i.e., biomass, wind, and solar energy is getting attention recently. Using photosynthetic organisms, algae is a viable alternative to produce food, feed, and fuels as algae are considered as one of the most robust species and commercially exploited for CO2 capturing or for water clean-up (i.e., remove pollutants and heavy metals at industrial settings). Very few produce high-value products using algae, e.g., carotenoids, vitamins, and pharmaceuticals that required extensive process integration and clean operations, but biohydrogen production using the algal platform was very scarce. Considering the future clean, green, and bio-circular economy, using algal technology to produce clean fuel hydrogen will be attractive and scalable. This chapter has summarized and culminated the literature about algal microbiology, mechanisms involved in the production of biohydrogen techniques, and the various secondary metabolites co-produced during the process of the algal hydrogen production platform. The chapter also listed and discussed the effect of various parameters on improving the biohydrogen yield and knowledge gaps to address shortly.

Nanotechnology is an interesting field in which molecules that are not visible to our eyes are creating wonders. They exist in various fields of engineering and science such as electronics, agriculture, food, pharmaceuticals, and medical diagnostics, and many researchers are eyeing provision of better technology with these nanotechnological inventions. Nanomaterials show great promise, owing to their unique physicochemical properties, in the field of agriculture. Plants interact with these nanoparticles, resulting in various morphological, physiological, and genotoxic changes. Understanding of their interactions is very important for real gains in the potential use of nanotechnology in agriculture. Nanoparticles have been described as “magic bullets.” Nanoparticles can play a vital role in the growth of plants and help in the process of photosynthesis. They also influence the key processes that take place in the growth of plants, such as seed germination, root initiation, and the photosynthetic process. Plant nanobionics is a current topic in which engineered nanomaterials are combined with plant organelles to enhance the function of plants. This chapter discusses various applications of plant nanobionics in detail.

Fermentation is an attractive field in the area of bioprocess engineering where it represents a promising and environmentally friendly option to find an alternative for the well-established chemical process which is being used currently. With the various fermentation techniques available, various microorganisms are utilized to an extent in producing a wide range of products which range from the production of biofuels from various sources of algae, bacteria, yeasts, etc. Apart from the various renewable sources, microorganisms are even capable to synthesize a wide range of fermented food products from various biological sources. In this chapter, we have discussed various advantages of fermented products as well as explained the various renewable energy sources which are the most needed for the survival of mankind.

International audience; This review provides the alternative routes towards the valorization of dark H-2 fermentation effluents that are mainly rich in volatile fatty acids such as acetate and butyrate. Various enhancement and alternative routes such as photo fermentation, anaerobic digestion, utilization of microbial electrochemical systems, and algal system towards the generation of bioenergy and electricity and also for efficient organic matter utilization are highlighted. What is more, various integration schemes and two-stage fermentation for the possible scale up are reviewed. Moreover, recent progress for enhanced performance towards waste stabilization and overall utilization of useful and higher COD present in the organic source into value-added products are extensively discussed.

Algae are single or multicellular photosynthetic organisms that can fix the atmospheric carbon into valuable lipids, proteins, carbohydrates, and fats. These algae are also capable of growing vigorously in different habitats from freshwater to brackish water environments and wastewater streams with nutrient uptake ability. These features make the algae themselves uniquely important in biofuel generation and wastewater treatment process along with CO2 sequestrations without competing with food crop land. The algae can also be used as a substrate for various biofuel generations, bioethanol, bio-butanol, hydrogen, methane, and many commercially valuable products. The applicability and renewability of algal fuel are most promising for the future biotechnological applications. Optimization of algal growth conditions and harvesting technology with desired biofuel generations at low processing cost can make the algae as one of the best sources of energy for future generations. Genetically modified algae which are capable to grow rapidly with generating high cellular lipids and carbohydrate content can be crucial for future energy demand.

In recent years, hydrogen (H2) has emerged as a clean and attractive substitute fuel since it can be produced from renewable energy sources. Upon combustion of hydrogen, it generates only water as a major by-product. In hydrogen and fuel cell technology, hydrogen can be applied in fuel cell technology; it produces only water as a major by-product with high energy yield, hold great potential for meeting in a quite unique way by empowering the so-called hydrogen-based economy. To make hydrogen-based economy viable, it is crucial to use renewable resources in place of fossil fuels to produce hydrogen. In this direction, by considering attractive and renewable characteristics of hydrogen led us to improve a variety of biological processes for the production of hydrogen. Nonetheless, commercialization of the biological process depends on improvements in process design along with an understanding of the nature of hydrogen producing communities and process optimization. Thus, this chapter highlights the major factors involved towards the improvement of biohydrogen production processes. Environmental impact of hydrogen as carbon-neutral energy carrier is also discussed. This also includes a technical and economic analysis of the biohydrogen and its role in the proposed hydrogen economy coupled with fuel cell and in transport application. Technological advancements based on hydrogen-based fuel cell designs and process integration approaches are also discussed.

Marine pollution is becoming more and more serious, especially in coastal areas. Because of the sequestration and consequent accumulation of pollutants in sediments (mainly organic compounds and heavy metals), marine environment restoration cannot exempt from effective remediation of sediments themselves. It has been well proven that, after entering into the seawater, these pollutants are biotransformed into their metabolites, which may be more toxic than their parent molecules. Based on their bioavailability and toxic nature, these compounds may accumulate into the living cells of marine organisms. Pollutants bioaccumulation and biomagnification along the marine food chain lead to seafood contamination and human health hazards. Nowadays, different technologies are available for sediment remediation, such as physicochemical, biological, and bioelectrochemical processes. This paper gives an overview of the most recent techniques for marine sediment remediation while presenting sediment-based microbial fuel cells (SMFCs). We discuss the issues, the progress, and future perspectives of SMFC application to the removal of hydrocarbons and metals in the marine environment with concurrent energy production. We give an insight into the possible mechanisms leading to sediment remediation, SMFC energy balance, and future exploitation.