With the present climate change and increasing world population, there is an urgent need to discover creative, efficient, and cost-effective natural products for the benefit of humanity. Biosurfactants are produced by various microorganisms that have several distinct properties compared to other synthetic surfactants, including mild production conditions, multifunctionality, higher biodegradability, and lower toxicity of living cells synthesis of active compounds. Due to their surface tension reducing, emulsion stabilizing, and biodegrading properties of these in place of chemical surfactants, they are generating huge demand in terms of research and usage. Biosurfactants are widely used in the food industry as food-formulation ingredients and antiadhesive agents as emulsifiers, de-emulsifiers, spreading agents, foaming agents, and detergents that find application in various fields such as agriculture, industrial sectors, and environmental recreation. Recent research focused more on heavy metal bioremediation from compost was achieved using biosurfactants-producing bacteria, which resulted in an improvement in compost quality. Although a number of studies on biosurfactants synthesis have been reported, very limited information on its cinematics and the consumption of renewable substrates are available. In this review paper, we made an attempt to critically review biosurfactants, their usage, research related to them, and challenges faced.

Providing safe drinking water and clean water is becoming a more challenging task all around the world. Although some critical issues and limits remain unsolved, implementing ecologically sustainable nanomaterials (NMs) with unique features, e.g., highly efficient and selective, earth-abundance, renewability, low-cost manufacturing procedures, and stability, has become a priority. Carbon nanoparticles (NPs) offer tremendous promise in the sectors of energy and the environment. However, a series of far more ecologically friendly synthesis techniques based on natural, renewable, and less expensive waste resources must be explored. This will reduce greenhouse gas emissions and harmful material extraction and assist the development of green technologies. The progress achieved in the previous 10 years in the fabrication of novel carbon-based NMs utilizing waste materials as well as natural precursors is reviewed in this article. Research on carbon-based NPs and their production using naturally occurring precursors and waste materials focuses on this review research. Water treatment and purification using carbon NMs, notably for industrial and pharmaceutical wastes, has shown significant potential. Research in this area focuses on enhanced carbonaceous NMs, methods, and novel nano-sorbents for wastewater, drinking water, groundwater treatment, as well as ionic metal removal from aqueous environments. Discussed are the latest developments and challenges in environmentally friendly carbon and graphene quantum dot NMs.