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© 2020 Elsevier B.V. Bioremediation through biotechnological interventions has attracted more attention among researchers in field of environmental pollution control and abatement. Various cutting-edge studies in area of protein engineering and synthetic biology offer a new platform for creation of innovative, advanced biological materials for its beneficial role in environmental pollution mitigation. Biocatalysis especially receives considerable attention as sustainable approach to resource recovery from waste along with elimination of pollutants. This paper focuses on updated developments in engineering of biocatalytic substances which can degrade pollutants of emerging concern. It also explains various classes of biocatalysts, their mechanisms of immobilization, and applications in terms of environmental pollutant remediation. Opportunities and challenges for future research have also been discussed.

Food waste is becoming a major global concern especially in developing and underdeveloped countries. Vegetable and food waste biomass is continuously generated in huge amounts. Its major impact on the environment is the generation of greenhouse gases. Food wastes are generated at different stages like production, handling, storage, processing, as well as consumption. First-generation technologies used for food waste disposal include landfill, incineration, and composting. But these strategies are not satisfactory for food wastes since they produce toxic methane gas and bad odor and have slow reaction kinetics. This can be addressed to a certain extent by adopting alternative strategies of food waste valorization by converting wastes to value-added products like fuels and chemicals. Food waste valorization will provide a green process with least environmental impact. This chapter discusses the latest trends in food waste valorization for the production of fuels and chemicals.

A large volume of solid and liquid waste is generated due to industrial and urban/suburban/agricultural activities. Management and handling of waste generated is nowadays burning issue for local authorities not only in urban areas, i.e., municipalities, but also in other regions in any country. With increasing urbanization and industrialization, generation of waste/wastewater appropriate disposal, treatment, and/or recycling are posing more challenges as the treatment and disposal costs huge amount in terms of money. However, conceiving the fact that “waste” word is placed wrongly and that it is a resource, resource recovery from wastes has emerged as thrust area of research and management as it offers huge environment and social sustainability potentials. Current researches globally are focusing on the recovery of various resources such as energy, bioproducts, nutrients, metals from waste/wastewater generated by anthropogenic activities, etc. This information needs to be discussed in the present context, and the future perspectives should be explored; most importantly, it should reveal current status, with state-of-the-art information and possibilities for technological exploitation. This chapter elaborates the recovery of various resources from solid and/or liquid waste.

In recent times, demand for energy has significantly increased due to the depletion of fossil fuels and the fast-industrial revolution. This has created a wide space for the development of sustainable and renewable energy sources. Biodiesel has attained exceptional contemplation among other biofuels due to the use of renewable and low-cost resources. Selection of suitable catalyst plays a vital role in biodiesel production by a catalytic transesterification reaction. Compared to homogeneous catalysts, heterogeneous catalysts are most preferred as they have high selectivity and stability with increased biodiesel yield. Heterogeneous catalyst has made incredible development in biodiesel production under mild operating conditions and has less impact on the environment. Nanocatalysts are the effective heterogeneous catalyst, which has brought a tremendous revolution in biodiesel production in recent years. Thus, present review provides a comprehensive analysis of the use of heterogeneous catalyst, importance and challenges associated in biodiesel production. (c) 2020 Elsevier B.V. All rights reserved.

Petroleum is produced by thermal decay of buried organic material over millions of years. Petroleum oilfield ecosystems represent resource of reduced carbon which favours microbial growth. Therefore, it is obvious that many microorganisms have adapted to harsh environmental conditions of these ecosystems specifically temperature, oxygen availability and pressure. Knowledge of microorganisms present in ecosystems of petroleum oil reservoirs; their physiological and biological properties help in successful exploration of petroleum. Understanding microbiology of petroleum oilfield(s) can be used to enhance oil recovery, as microorganisms in oil reservoirs produce various metabolites viz. gases, acids, solvents, biopolymers and biosurfactants. The aim of this review is to discuss characteristics of petroleum oil reservoirs. This review also provides an updated literature on microbial ecology of these extreme ecosystems including microbial origin as well as various types of microorganisms such as methanogens; iron, nitrate and sulphate reducing bacteria, and fermentative microbes present in petroleum oilfield ecosystems.

Crude glycerol, one of the ever-growing by-product of biodiesel industry and is receiving the closest review in recent times because direct disposal of crude glycerol may emerge ecological issues. The renewability, bioavailability and typical structure of glycerol, therefore, discover conceivable application in serving the role of carbon and energy source for microbial biosynthesis of high value products. This conceivable arrangement could find exploitation of crude glycerol as a renewable building block for bio-refineries as it is economically as well as environmentally profitable. In this review, we summarize the uptake and catabolism of crude glycerol by different wild and recombinant microorganism. The chemical and biochemical transformation of crude glycerol into high esteem malic acid by various microbial pathways is also additionally discussed. An extensive investigation in the synthesis of high-value malic acid production from various feed stock which finds applications in cosmeceutical and chemical industries, food and beverages, and to some extent in the field of medical science is also likewise studied. Finally, the open doors for unrefined crude glycerol in serving as a promising abundant energy source for malic acid production in near future have been highlighted. (C) 2019 Elsevier B.V. All rights reserved.