Global perspective of municipal solid waste and landfill leachate: generation, composition, eco-toxicity, and sustainable management strategies.

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate.

Insights into the toxicity and biodegradation of fipronil in contaminated environment.

Fipronil is a phenylpyrazole insecticide used in various agricultural, horticulture, and veterinary practices. Besides its wide range of applications, it also causes severe health hazards to the non-targeted organisms especially in developing countries. Fipronil showed hepatotoxic, nephrotoxic, neurotoxic, and altered reproductive development and endocrine system in humans and animals. Several methods have been already introduced for the removal of toxic fipronil including physicochemical and by the implementation of microorganisms. The microbial methods of fipronil degradation are the most promising and environmentally sustainable. The remediation of fipronil from the environment is an emerging task due to its enhanced residual concentration. Herein, we discuss the bioremediation potential of microbial strains in contaminated soil and water. It is shown that fipronil can be remediated from the environment using combined ecotechnologies. This review discusses the toxicity, different physico-chemical and biological methods, and sustainable developments in fipronil-contaminated agriculture and aquatic environments.

Bioactive Compounds from Cocoa Husk: Extraction, Analysis and Applications in Food Production Chain.

Cocoa husk is considered a waste product after cocoa processing and creates environmental issues. These waste products are rich in polyphenols, methylxanthine, dietary fibers, and phytosterols, which can be extracted and utilized in various food and health products. Cocoa beans represent only 32-34% of fruit weight. Various extraction methods were implemented for the preparation of extracts and/or the recovery of bioactive compounds. Besides conventional extraction methods, various studies have been conducted using advanced extraction methods, including microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), subcritical water extraction (SWE), supercritical fluid extraction (SFE), and pressurized liquid extraction (PLE). To include cocoa husk waste products or extracts in different food products, various functional foods such as bakery products, jam, chocolate, beverage, and sausage were prepared. This review mainly focused on the composition and functional characteristics of cocoa husk waste products and their utilization in different food products. Moreover, recommendations were made for the complete utilization of these waste products and their involvement in the circular economy.

Anthocyanins, multi-functional natural products of industrial relevance: Recent biotechnological advances.

Anthocyanins, the color compounds of plants, are known for their wide applications in food, nutraceuticals and cosmetic industry. The biosynthetic pathway of anthocyanins is well established with the identification of potential key regulatory genes, which makes it possible to modulate its production by biotechnological means. Various biotechnological systems, including use of in vitro plant cell or tissue cultures as well as microorganisms have been used for the production of anthocyanins under controlled conditions, however, a wide range of factors affects their production. In addition, metabolic engineering technologies have also used the heterologous production of anthocyanins in recombinant plants and microorganisms. However, these approaches have mostly been tested at the lab- and pilot-scales, while very few up-scaling studies have been undertaken. Various challenges and ways of investigation are proposed here to improve anthocyanin production by using the in vitro plant cell or tissue culture and metabolic engineering of plants and microbial culture systems. All these methods are capable of modulating the production of anthocyanins , which can be further utilized for pharmaceutical, cosmetics and food applications.

Improved lead removal from aqueous solution using novel porous bentonite - and calcite-biochar composite.

Biochar-mineral (bentonite/calcite) composite (BC-CM) prepared at different temperatures were tested under varied conditions for effective removal of lead (Pb) from aqueous solution. With increasing pyrolysis temperature, increased surface area, pore volume, bentonite decomposition and less or no decomposition of calcite occurred. Bentonite-biochar (BCS) and calcite-biochar (CCS) prepared at 700 °C were found most suitable for efficient removal of Pb (99.9%). Bentonite and calcite acted as catalyst and contributed to changes in yield, pH, texture, functional groups, minerals and carbonization that facilitated efficient Pb removal by BCS 700 and CCS 700. Pb concentration, pH, dose of BCS and CCS, and contact time were further optimized using response surface methodology (RSM) for maximizing removal percentage (R%) of Pb and adsorption capacity (qt). Both BCS 700 and CCS 700 showed similar effects (positive/negative) of factors on R% and qt. Under optimized conditions, 0.21 g of BCS 700 effectively removed 99.2% of 431 mg/L in 3.6 h at solution pH of 4.2, while 0.07 g CCS 700 removed 97.06% of 232 mg/L in 3.5 h at 5.5 pH. Removal of Pb onto both BCS and CCS was by monolayer adsorption with maximum adsorption capacity of 500 mg/g. Rapid Pb removal was observed within 2 h of contact time (CCS 700 > BCS 700) and equilibrium was achieved within 10 h. BCS 700 followed first order and CCS 700 followed second order kinetic model. Electrostatic attraction between Pb ions and mineral groups present in BCS 700 and CCS 700 also played important role in Pb removal. This study clearly demonstrated that composite of biochar with bentonite or calcite under optimized conditions significantly improved Pb removal and adsorption capacity that can be further utilized for larger scale applications.

Implications of grape extract and its nanoformulated bioactive agent resveratrol against skin disorders.

The grape seed extract (GSE) and its main active polyphenol, resveratrol (RES), have shown considerable antioxidant activities, besides possessed protective and therapeutic effects against various skin complications. This paper discusses the favorable effects of RES, GSE and their nanoformulations for dermatological approaches, with specific emphasis on clinical interventions. In this manner, electronic databases including PubMed, Science Direct and Google Scholar were searched. Data were collected from 1980 up to February 2019. The search terms included "Vitis vinifera", "grape", "resveratrol", "skin", "dermatology", and "nanoformulation". To increase the skin permeability of GSE and RES, several innovative nanoformulation such as liposomes, niosomes, solid-lipid nanoparticles, nanostructured lipid carriers, and lipid-core nanocapsule has been evaluated. According to our extensive searches, both RES and GSE have beneficial impacts on skin disorders such as chloasma, acne vulgaris, skin aging, as well as wound and facial redness. More clinical studies with nanoformulation approaches are recommended to achieve conclusive outcomes regarding the efficacy of RES and GSE in the management of skin diseases.