Valorization of food industrial waste into protein amyloid fibrils for water and energy applications

• Main Author: Soon, Wei Long
• Other Authors: Ali Gilles Tchenguise Miserez
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering
• Online Access: https://hdl.handle.net/10356/174078
• Institution: Nanyang Technological University

Technological practices since the past few decades have resulted in negative impacts on the environment and climate today due to unsustainable manufacturing. In order to achieve a more sustainable economy, it is paramount to develop new technologies involving renewable resources along with low to no greenhouse gas emissions. One large detrimental area contributing to rising greenhouse gas emissions is industrial food waste which produces up to 10% of global emissions from the annual billion-ton waste generation. In a growing world population where reducing food production is not a feasible solution, these generated food waste would be more suited to instead be reintroduced back into the food chain or reutilized for other applications. Possessing a diverse amino acid composition, proteins are functional macronutrients that are valuable not only as food but also new biomaterials for green technologies, for which the areas of water purification and renewable energy are explored in this thesis using chicken feathers and oilseed meals as food waste sources. Moreover, proteins in the form of amyloid fibrils have improved functionality due to their increased surface area and rigidity, and hence serve as promising materials for these targeted applications. As a major pollutant in polluted water, heavy metals accumulate in the body and cause diseases and even death. The removal of heavy metals to produce clean drinkable water is however still relatively expensive due to high power consumption. To address the need for a potentially affordable and greener alternative, proteins derived from chicken feathers and plants were turned into amyloid fibrils and mixed with activated carbon to produce reusable filtration membranes capable of removing toxic heavy metals (platinum, chromium, lead) from contaminated water into drinkable standard water according to WHO. The high heavy metal adsorption capacities of the amyloid fibrils coupled with the porous structure of activated carbon allowed the filtration process to be performed under gravity and thus reducing the energy input needed for clean water generation. As one of the developing renewable energy technologies, fuel cells are promising technologies due to their advantage of zero carbon emissions. The heart of the fuel cell consists of a proton exchange membrane to allow the flow of protons during operation. Current state-of-the-art membranes made from perfluorinated polymers used in commercial fuel cells remain costly and are produced from environmentally unfriendly manufacturing processes. The similarity and unique composition of proteins from chicken feathers enabled the fabrication of a bio-based proton conductive membrane that was successfully incorporated into a hydrogen fuel cell to power several devices, presenting a potential green material for future energy generation. The main highlight of this work is the valorization of industrial food waste into sustainable technologies to produce drinkable water and clean energy. The developed green extraction and fabrication processes without the usage of toxic solvents allow the facile scaling of these sustainable technologies, which provide new useful applications for these industrial wastes to achieve a circular economy.