Author : Derek Troiano
Release : 2022
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Kind : eBook
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Book Synopsis Biotransformation of Biomass Waste Residues Into Value-added Chemicals Using Filamentous Fungi by : Derek Troiano

Download or read book Biotransformation of Biomass Waste Residues Into Value-added Chemicals Using Filamentous Fungi written by Derek Troiano. This book was released on 2022. Available in PDF, EPUB and Kindle. Book excerpt: "Use of biomass as feedstock for the production of carbon-based fuels and chemicals represents an essential component of the global strategy to attain sustainable and circular industrial economies. Current strategic objectives for biomass conversion technologies focus on enhancing cost competitiveness through, for example, the use of cheaper feedstocks (e.g. lignocellulosic wastes). However, adoption of lignocellulosic biomass as substrate will only be possible after addressing the inefficiencies and costs which stem from the additional processing necessitated by the compositional complexity of lignocellulosic materials. Nature, wherein the recycling of lignocellulosics is an essential ecological process, may offer strategies for engineers and scientists to emulate. Fungi, particularly filamentous fungi, are well-known for their role as material recyclers in the natural carbon cycles and, as such, are intriguing for use in biomass-conversion, or biorefining processes. Concerning the products of fungal biotransformations, the number of potential products is proportional to the number of metabolites associated with a given organism; and these metabolic products remain largely underexplored or altogether unidentified. Therefore, a method for screening and evaluating a large number of products that may be obtained from fungal biotransformation of various biomass feedstocks was developed as part of the study described herein. Identified among the products were valuable chemicals, such as those described in two recent US Department of Energy surveys, including furans and organic acids. In addition to these "top chemical opportunities", substantial production of bio-pigments was also observed. Of the feedstocks investigated, a simulated food-waste feedstock was associated with the highest pigment production and was thus further investigated for maximal pigment production. To that end, an optimized extraction method was employed and, following this, a novel strategy was explored involving co-culturing of multiple strains of fungi together in a single conversion reaction. It was found that co-culturing the pigment-producing fungus with a specific second species elicited significantly more pigment production vis-à-vis the pigment-producing species alone. 2,5-furandicarboxylic acid (FDCA), a compound of industrial interest for use as a replacement for terephthalic acid in polymer production, was also identified among the fungal biotransformation products of apple pomace feedstock. Since FDCA is mainly produced via oxidation of 5-hydroxymethylfurfural (HMF), itself a carbohydrate-derived product, the process of using filamentous fungi for converting HMF into FDCA was more closely investigated. Several industrially relevant strains of filamentous fungi, including the strain used throughout this project (Talaromyces sp. NRRL 2120), were screened for oxidative activity on HMF. It was found that multiple strains of fungi readily performed one oxidation on HMF (i.e. converted HMF into its acid counterpart) but accumulated very little, if any, FDCA under the given reaction conditions. To enable additional oxidation steps, a chemo-biocatalytic cascade involving the best-performing fungal strain coupled with an enzyme/mediator system was devised. This system enabled full conversion of HMF into FDCA and achieved the highest yield and productivity for any system involving filamentous-fungal whole-cells. Following this, the ability to reuse the whole-cell biocatalysts for multiple reactions was explored via encapsulation of the filamentous fungal whole cells. Here it was found that encapsulation of the fungal cells in Ca-alginate beads enabled the biocatalysts to be reliably recycled for up to nine reaction cycles"--