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Biohydrogen is perceived as the versatile fuel of the future, having the ability to replace fossil fuels in many industrial and commercial sectors and offering the promise of fulfilling future renewable energy demands. Among various options available for the generation of biohydrogen, photofermentation with the help of microbes and algae is one of the most eye-catching approaches due to its relative efficiency, cost economics, and reduced environmental impacts. Generation of biohydrogen by dark fermentation, microbial electrolysis cell as well as photofermentation, along with their bioprocesses, already have been discussed in earlier literature. Photofermentation offers advantages of both biophotolysis (utilization of light energy) and dark fermentation (utilization of organic waste materials as substrate). Many researchers have been reported successful biohydrogen production from photofermentation-based techniques, however not much information is available regarding the considerable gap in industrial and economic challenges in the production of biohydrogen at the commercial level through photofermentation. Efforts have been made in this review to provide updated information on various new technologies being used in this sector, such as the integration of photofermentation with dark fermentation, the use of recombinant DNA technology, and the use of bionanotechnology to improve biohydrogen production through the utilization of various waste. Various challenges in this sector, as well as future perspectives, have been meticulously addressed in order to explore the future of green biohydrogen production for a sustainable future. [Display omitted] • Biohydrogen is versatile, efficient, economic, and carbon-neutral biofuel. • Microbial production from organic wastes provides environmental sustainability. • Integrated bioreactors for dark and photofermentation provide better efficiency. • Engineered microbes and bionanotechnology key players for industrial applications. [ABSTRACT FROM AUTHOR]

Waste rice straw biomass and its burning in open fields have become a serious issue of greenhouse gases emission and air pollution, which has a negative impact on public health and the environment. However, the environmental impact of burning this agro-waste can be mitigated by diverting it towards green biorefinery through the sustainable production of energy, biofuels, organic chemicals, and building blocks for various polymers. This will not only help to reduce the reliance on limited fuels and various chemicals derived from petroleum, but also help in the restoration of the environment in a sustainable manner through its complete utilization. To maximize the inherent conversion potential of rice straw biomass into valuable products, this agriculture waste biomass requires a comprehensive analysis and a techno-economic review for its sustainable management. This review article focuses on the sustainable management of rice straw waste biomass via innovative valorization approaches, as well as the opportunities and challenges encountered in this sector for meeting the demand of current and future green biorefineries. [ABSTRACT FROM AUTHOR]

Petrochemicals are important hydrocarbons, which are one of the major concerns when accidently escaped into the environment. On one hand, these cause soil and fresh water pollution on land due to their seepage and leakage from automobile and petrochemical industries. On the other hand, oil spills occur during the transport of crude oil or refined petroleum products in the oceans around the world. These hydrocarbon and petrochemical spills have not only posed a hazard to the environment and marine life, but also linked to numerous ailments like cancers and neural disorders. Therefore, it is very important to remove or degrade these pollutants before their hazardous effects deteriorate the environment. There are varieties of mechanical and chemical methods for removing hydrocarbons from polluted areas, but they are all ineffective and expensive. Bioremediation techniques provide an economical and eco-friendly mechanism for removing petrochemical and hydrocarbon residues from the affected sites. Bioremediation refers to the complete mineralization or transformation of complex organic pollutants into the simplest compounds by biological agents such as bacteria, fungi, etc. Many indigenous microbes present in nature are capable of detoxification of various hydrocarbons and their contaminants. This review presents an updated overview of recent advancements in various technologies used in the degradation and bioremediation of petroleum hydrocarbons, providing useful insights to manage such problems in an eco-friendly manner. [ABSTRACT FROM AUTHOR]

Continuous urbanization and modernization have increased the burning of fossil fuels to meet energy needs across the globe, emanating environmental pollution and depleting fossil fuels. Therefore, a shift towards sustainable and renewable energy is necessary. Several techniques to exploit biomass to yield energy are trending, with pyrolysis one of them. Usually, a single feedstock is employed in pyrolysis for anoxygenic generation of biochar together with bio-oil at elevated temperatures (350–600 °C). Bio-oil produced through pyrolysis can be upgraded to crude oil after some modification. However, these modifications of bio-oil are one of the major drawbacks for its large-scale adoption, as upgradation increases the overall cost. Therefore, in recent years the scientific community has been researching co-pyrolysis technology that involves the pyrolysis of lignocellulosic biomass waste with non-biodegradable waste. Co-pyrolysis reduces the need for post-modification of bio-oil, unlike pyrolysis of a single feedstock. This review article discusses the recent advancements and technological challenges in waste biomass co-pyrolysis, the mechanism of co-pyrolysis, and factors that affect co-pyrolysis. The current study critically analyzes different recent research articles presented in databases such as PubMed, MDPI, ScienceDirect, Springer, etc. Hence, this review is one-of-a-kind in that it attempts to explain each and every aspect of the co-pyrolysis process and its current progress in the scientific field. Consequently, this review also compiles the remarkable achievements in co-pyrolysis and recommendations for the future. [ABSTRACT FROM AUTHOR]

Petrochemicals are important hydrocarbons, which are one of the major concerns when accidently escaped into the environment. On one hand, these cause soil and fresh water pollution on land due to their seepage and leakage from automobile and petrochemical industries. On the other hand, oil spills occur during the transport of crude oil or refined petroleum products in the oceans around the world. These hydrocarbon and petrochemical spills have not only posed a hazard to the environment and marine life, but also linked to numerous ailments like cancers and neural disorders. Therefore, it is very important to remove or degrade these pollutants before their hazardous effects deteriorate the environment. There are varieties of mechanical and chemical methods for removing hydrocarbons from polluted areas, but they are all ineffective and expensive. Bioremediation techniques provide an economical and eco-friendly mechanism for removing petrochemical and hydrocarbon residues from the affected sites. Bioremediation refers to the complete mineralization or transformation of complex organic pollutants into the simplest compounds by biological agents such as bacteria, fungi, etc. Many indigenous microbes present in nature are capable of detoxification of various hydrocarbons and their contaminants. This review presents an updated overview of recent advancements in various technologies used in the degradation and bioremediation of petroleum hydrocarbons, providing useful insights to manage such problems in an eco-friendly manner. [ABSTRACT FROM AUTHOR]

Proteases are ubiquitous enzymes, having significant physiological roles in both synthesis and degradation. The use of microbial proteases in food fermentation is an age-old process, which is today being successfully employed in other industries with the advent of 'omics' era and innovations in genetic and protein engineering approaches. Proteases have found application in industries besides food, like leather, textiles, detergent, waste management, agriculture, animal husbandry, cosmetics, and pharmaceutics. With the rising demands and applications, researchers are exploring various approaches to discover, redesign, or artificially synthesize enzymes with better applicability in the industrial processes. These enzymes offer a sustainable and environmentally safer option, besides possessing economic and commercial value. Various bacterial and fungal proteases are already holding a commercially pivotal role in the industry. The current review summarizes the characteristics and types of proteases, microbial source, their current and prospective applications in various industries, and future challenges. Promoting these biocatalysts will prove significant in betterment of the modern world. [ABSTRACT FROM AUTHOR]