Bioreactor scale co-production of poly(hydroxyalkanoate) and rhamnolipids with distinct nitrogen sources

Integrated production of polyhydroxyalkanoates and rhamnolipids: Insights in cultivation conditions and metabolic engineering

Polyhydroxyalkanoates and biosurfactants have the potential to play a significant role in emerging bioeconomic chains. With growing environmental worries about the excessive consumption of fossil fuel derivatives, significant focus has been paid to a renewable-based economy known as the circular bioeconomy. Polyhydroxyalkanoates (PHAs) are a type of biodegradable, hydrophobic, non-toxic, thermoplastic polymer created by microbial processes that have good physicochemical properties. Rhamnolipids (RhL) are amphipathic, biodegradable, and biocompatible compounds with outstanding emulsification capabilities. Unfortunately, commercial manufacturing of PHA and RhL remains limited due to their high production costs as compared to standard polymers and surfactants. The combined manufacture of PHA and RhL can lower production costs and is an ideal option for creating two widely applicable commodities on the market. This work provides a general overview of PHA and RhL co-production, focusing on the use of renewable materials and important aspects that are directly related to cultivation conditions, as well as genetic and metabolic engineering strategies to optimize PHA and RhL production.

Arsenic in drinking water: overview of removal strategies and role of chitosan biosorbent for its remediation

Accessibility to clean drinking water often remains a crucial task at times. Among other water pollutants, arsenic is considered a more lethal contaminant and has become a serious threat to human life globally. This review discussed the sources, chemistry, distribution, and toxicity of arsenic and various conventional technologies that are in option for its removal from the water system. Nowadays, biosorbents are considered the best option for arsenic-contaminated water treatment. We have mainly focused on the need and potential of biosorbents especially the role of chitosan-based composites for arsenic removal. The chitosan-based sorbents are economically more efficient in terms of their, low toxicity, cost-effectiveness, biodegradability, eco-friendly nature, and reusability. The role of various modification techniques, such as physical and chemical, has also been evaluated to improve the physicochemical properties of biosorbent. The importance of adsorption kinetic and isotherm models and the role of solution pH and pHPZC for arsenic uptake from the polluted water have also been investigated. Some other potential applications of chitosan-based biosorbents have also been discussed along with its sustainability aspect. Finally, some suggestions have been highlighted for further improvements in this field.