Biomass feedstocks extraction

Although CO2 is inhibitory to microbes, compressed hydrocarbon solvents may be appropriate for extractive bioconversions and extractions in biphasic (aqueous-compressed solvent) systems. Our laboratory investigated the metabolic activity of the anaerobic, thermophilic bacteria Clostridium ther-mocellum as a model system (45). Thermophilic bacteria have a distinct advantage over conventional yeasts for ethanol production in their ability to use a variety of inexpensive biomass feedstocks. Extractive fermentation using compressed solvents is an approach to address the end-product toxicity of these bacteria to ethanol and improve the economic viability of biofuel production by thermophilic organisms. 

The second greener alternative that can resonate with the organic chemistry audience is biomass feedstocks, chemicals that are directly extracted from renewable sources (Tokay 2005). Biomass feedstocks... 

The global natural gas resources are considered abundant, and they are conservatively estimated to be between 1.1 and 1.7 times as large as all the natural gas that has already been extracted or found in proven reserves.6 In the absence of natural gas, naphtha, or fuel oil, ammonia synthesis could proceed easily (albeit more costly) by tapping the world s enormous coal deposits or using a variety of biomass feedstocks. 

In the United States and most industrialized countries, the practical value of the commercial production of an organic chemical from biomass depends strongly on the availability and price of the same chemical produced from petroleum or natural gas, and occasionally coal. As will be shown shortly, there is no technical barrier that precludes production of commodity chemicals from biomass feedstocks. And it will become evident that many of the more complex organic chemicals are best synthesized from biomass feedstocks or can be extracted from appropriate biomass species. These chemicals can also be synthesized from hydrocarbon feedstocks, but the costs are often prohibitive. In the midst of the fossil fuel era, the less complex, commodity organic chemicals are preferentially manufactured from petroleum or natural gas, whereas complex specialty chemicals are derived from biomass. But commodity organic chemicals are open to entry by biomass feedstocks if they can provide economic advantages. Note that many of the routes described here to commodity chemicals from biomass were in commercial use in the past, are still in commercial use, have recently been commercialized, or have been developed and are available for commercial use. 

Finally, Phase III biorefineries are the most advanced, as they use a variety of biomass feedstock to yield a mix of products (Figure 1.2). Such biorefineries employ a combination of technologies, among them are chemical and/or biological transformations, extractions, and separations. Examples for Phase III biorefineries include whole-crop biorefineries encompassing an array of transformations of feedstock (e.g., corn, or rapeseed). The most promising type of Phase HI biorefineries are... 

Biomass and Biochemical Processes. Phenolic resins have been produced from biomass and using biochemical processes in various ways. In Japan biomass from wood waste or waste from the food industry is treated with phenols and strong acid catalysis and heat to produce phenolic resins (88). Research at the National Renewable Energy Laboratory has shown that ablative fast pyrolysis can be used to convert a wide variety of biomass feedstocks into a liquid oil. The phenolic rich component can be extracted from this oil and used as a low cost replacement for synthetic phenol in phenolic resins (89). In another approach, soybean peroxidase enzymes have been used to prepare resins from phenolic moieties without the use of formaldehyde (90). 

Research continues to explore the HT of bio-oil produced from new biomass feedstocks. Researchers at Pacific Northwest National Laboratory have reported several related investigations including the use of the phase-separated heavy less-aqueous fraction from bio-oU for production of liquid fuels and low-sidfur coke (Elliott et al., 2013a), bio-oU produced from mountain-pine-beetle-killed trees and hog fuel (Zacher et al., 2014), and the extractant-rich top phase from softwood pyrolysis (Elliott et al., 2012). Another study evaluated the HT of a bio-oU feedstock which was a phenolic oil recovered by fractionating and washing fast pyrolysis bio-oil (Elliott et al., 2015). 

The reliance of fossil fuels has been challenged by lower cost and renewable sources that are more environmentally friendly. The traditional chemical plant has met serious competition from green plants. Many monomers are now made via fermentation, using low-cost sugars as feedstock. Some of the commodity monomers are under siege by chemicals extracted from biomass. Monomer production has been expanded to include many more monomers from nature. 

Furfural - [BUTADIENE] (Vol 4) - [cross-reference entry] (Vol 12) - [EXTRACTION - LIQUm-LIQUID] (Vol 10) -from biomass [FUELS FROMBIOMASS] (Vol 12) -as chemical feedstock [FURANDERIVATIVES] (Supplement) -use of cast copper alloys with [COPPER ALLOYS - CAST COPPER ALLOYS] (V ol 7)... 

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