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Biodiesel, Power Alcohol and Butanol Production
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
The ABE-producing clostridia can use both hexose and pentose sugars. Hexose sugars are metabolized via an enzyme-catalysed pathway known as glycolysis. Pentoses are metabolized through the nonoxidative pentose phosphate pathway. Glycolysis produces two molecules of pyruvate which are further used for ABE fermentation (Jang et al., 2012).
Integrated bio-refinery process for mass production of silica, lignin, and nanocellulose from rice straw biomass
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Thai Dinh Cuong, Phan Huy Hoang
Currently in Vietnam, many tons of rice are harvested per year, and thus a large amount of rice straw is formed as agricultural by-products. This agricultural residue is often burned or eliminated to the surrounding environment after harvesting, causing waste and environmental pollution (Dien et al. 2014; Phuong et al. 2017). Rice straw biomass contains the components such as cellulose, hemicellulose, lignin, and silica which could be convert to various valuable biochemicals and products. Recently, the complex lignocellulose structure including aromatic and sugar moieties make it to be a potential feedstock for development of new bio-based productssustainable useful materials and can be valorized for the development of sustainable useful materials for batteries or pharmaceuticals formulation and various interesting applications (Beaucamp et al. 2019; Pishnamazi et al. 2019; Steinmetz et al. 2020). Hemicellulose containing of pentosan could be easily converted to pentose sugar by mild, selective, and acidic conversion process (Morais et al. 2016). This xylose then can be employed for transformation into important chemicals or fuels such as furfural (Hoang and Cuong 2021). The recovered organic silica can be used widely in electronics, ceramic, and polymer material industries. Thanks to their small-diameter, silica has been applied in many technological fields, such as reinforcing filler for preparation of composite, thermal insulators, an adsorbent in water treatment processes, as an organic coating against corrosion (An et al. 2010; Sun and Gong 2001). While obtained lignin, a source of valuable carbon material, can be used as an adsorbent, as a binder, surfactant, or as carbon resource for preparation of other useful material (Steinmetz et al. 2020).
Review on the synthesis, performance and trends of butanol: a cleaner fuel additive for gasoline
Published in International Journal of Ambient Energy, 2022
The algal biomass after being harvested is subjected to pretreatment. The method employed can be using an acid, alkali, enzyme or other mechanical techniques. The purpose of pretreatment is to furnish the sugars of the microalgal species to the fermentative bacteria. The various types of sugars present commonly in the algae are – glucose, mannose, galactose, rhamnose, fructose and fucose (hexose sugar). Xylose, arabinose and ribose are the pentoses found in addition to chemicals like galacturonic acid found in the cell walls of algae and glycerol which is accumulated as a result of osmostic stress in cytosol (Doan et al. 2012). All these sugars are fermented by bacteria. Pretreatment is thus of paramount importance for effective fermentation to take to place. Ulva lactuca feedstock when subjected to sulphuric acid pretreatment gave a lesser butanol yield when compared to the yield obtained when it was subjected to sulphuric acid and enzymes pretreatment (Potts et al. 2012; Van der Wal et al. 2013). The same feedstock Ulva lactuca when subjected to sodium hydroxide and enzymes pre-treatment did not give a measurable quantity of butanol (Van der Wal et al. 2013). This goes on to emphasise the importance of pretreatment in ABE fermentation. Mechanical pretreatment can be energy intensive, whereas chemical methods might suffer from inhibitory effects of leftover chemicals (Lee, Lewis, and Ashman 2012; Mendez et al. 2013). Some a combination of pre-treatment steps works best for getting good results. Enzymatic hydrolysis works well in helping us recover soluble sugar from the total carbohydrate content of the algal species but adds to the cost in a big way making it economically unviable. In most cases, however, a simple chemical hydrolysis is sufficed to obtain fermentable sugars (Wang et al. 2013).