Production of Ecofriendly Bio-dye using Microorganisms and their Applications to Biodegradable Polymers

Abstract

Recent advancements in biotechnology have widens the barriers that provides the opportunity develop a potential biodegradable polymers through a multifaceted approach. Encompass a wide range, including well known polymers like PHA (Poly(hydroxyalkanoate)), PLA (poly lactic acid), and PBS (poly alkylene succinate). Although these biodegradable polymers are environment friendly, they also have certain limitations. Firstly, the degradation rate of these polymers is often influenced by specific environmental conditions, making it challenging to precisely control the degradation timeline. Additionally, these polymers tend to have higher production costs and exhibit relatively modest mechanical properties, which place significant constraints on their widespread application. To overcome these challenges, efforts have been made to enhance their performance, regulate degradation, and improve their ecofriendliness through the incorporation of additives. Within the scope of my doctoral dissertation, the research has focused on the use of environmentally friendly biochemistry and the integration of microbially-derived dyes or pigments as additives to biodegradable polymers. Furthermore, these additives have been employed as functional chemicals to enhance the overall functionality and utility of the polymers._x000D_ <br>Firstly, a one-pot biosynthesis technique was employed to produce Indigo Derivatives-Incorporating Poly(3-hydroxybutyrate) (IDPs) using a modified E. coli strain. A spectrum of indigo derivatives was generated, each displaying unique physical and biological properties. These indigo derivatives were also employed as additives, providing the capability to regulate biodegradability. Each of the produced indigo derivative biodegradable films exhibited different antioxidant capacities, physical properties, and molecular weights, depending on their interaction with the PHB (polyhydroxybutyrate) polymer. This demonstrated that by modulating the indigo derivatives, it is possible to alter physiological and physical characteristics such as biodegradability, antioxidant capacity, and physical properties. Practical applications of these IDPs as coatings for cellulose were explored, resulting in various surface structures without compromising their color. _x000D_ <br>Secondly, Violacein, a well-known purple dye, is produced by microorganisms like Chromobacterium violaceum. It's famous for its anti-cancer, anti-tumor, and anti-malignant properties against human cells, as well as its antibacterial, antifungal, and antimicrobial effects on various microorganisms, including bacteria and archaea. Owing to these qualities, violacein has been extensively studied and used for various purposes. Its unique color and antimicrobial properties have led to its adoption as an additive in films and polymers. A composite, designated as poly-β-hydroxybutyrate-cellulose augmented with deoxyviolacein (PHB-DVCell), was synthesized. This composite combined the properties of L-tryptophan-derived deoxyviolacein and externally sourced cellulose, revealing interesting characteristics, especially the stability of deoxyviolacein molecules within the biodegradable layers. _x000D_ <br>Lastly, a breakthrough in addressing the historical issue of melanin's water-insolubility was achieved by developing an environmentally friendly melanin variant using genetically modified E. coli. This novel melanin chemical, derived from gallic acid, was successfully synthesized within genetically engineered E. coli, exhibiting superior antioxidant and antimicrobial properties when compared to conventional tyrosine-based melanin. Not only this, the new water-soluble gallic acid melanin also demonstrated enhanced thermal stability compared to traditional melanin, along with good electrical conductivity (0.136 S/cm). Overcoming one of the biggest drawbacks of conventional melanin, this novel melanin was applied in hydrogel sensors. The melanin-bound hydrogel sensors showed increased adhesiveness, enabling the detection of finger movements even on localized areas like a finger. Furthermore, leveraging the high antioxidant and antimicrobial properties of this water-soluble gallic acid melanin, it was applied to PVA films to explore its potential as food packagingmaterial._x000D_ <br>Together, these studies highlight the versatility of biodegradable polymers and their potential _x000D_ <br>in biotechnological applications. Essentially, this comprehensive research promises a colorful, _x000D_ <br>functional, and sustainable future in the domain of biodegradable polymers and organic pigments