Solvent extraction, biomass

Hemicellulose [9034-32-6] is the least utilized component of the biomass triad comprising cellulose (qv), lignin (qv), and hemiceUulose. The term was origiaated by Schulze (1) and is used here to distinguish the nonceUulosic polysaccharides of plant cell walls from those that are not part of the wall stmcture. Confusion arises because other hemicellulose definitions based on solvent extraction are often used in the Hterature (2—4). The term polyose is used in Europe to describe these nonceUulosic polysaccharides from wood, whereas hemicellulose is used to describe the alkaline extracts from commercial pulps (4). The quantity of hemicellulose in different sources varies considerably as shown in Table 1. 

Figure 2.5 Possible technological solutions to bioprocess problems a) Fed-batch culture b) Continuous product removal (eg dialysis, vacuum fermentation, solvent extraction, ion exchange etc) c) Two-phase system combined with extractive fermentation (liquid-impelled loop reactor) d) Continuous culture, internal multi-stage reactor e) Continuous culture, dual-stream multi-stage reactor f) Continuous culture with biomass feedback (cell recycling). (See text for further details).

Extraction into capsules with a solvent, for example, recovery of phenylethanol (a product of phenylalanine bioconversion by yeast) [67] or lactic acid from fermentation broth [68], has attracted interest recently. The polymeric core of the capsule prevents direct contact of the solvent with biomass. This process could be regarded as a batch MBSE. 

Primary recovery of the active ingredient from the solid or liquid phase to remove large quantities of unwanted waste materials, which may themselves be processed further. Suitable techniques include solvent extraction, precipitation by chemical or physical changes to the product-containing solution, and ultrafiltration or microfiltration to separate products above a particular size. Work done on combined biomass separation-primary product recovery processes such as expanded-bed adsorption are now being commercialized in the pharmaceutical industry. 

Lipopholic products are usually separated by extraction of the filtered broth, or the whole culture including the biomass, with water immiscible organic solvents, followed by separation of the solvent extracts and concentration in a vacuum evaporator. Chloroform, dichloromethane and ethyl acetate have been widely used as extraction solvents, however, 4-methyl-2-pentanone (methyl isobutyl ketone) appears to be the solvent of choice in the case of steroid substrates. Hydrophilic products, which cannot be extracted by organic solvents, can be isolated by ion exchange or by selective adsorption to polymeric resins (e.g., Amberlite XAD-resins). Resins of a wide range of polarity are available and lipophilic compounds can also be separated by this method. Final purification is accomplished in the usual way by crystallization, distillation or column chromatography. Preparative HPLC is a powerful tool for purification of small product quantities. 

FIGURE 10.1 Example of solvent extraction scheme for separating various components in hydrocarbon-containing biomass. 

The aim of this work was to develop a simple, environmentally sound and fltst method for the extraction and determination of squalene in an olive biomass using the PFE technique, and investigate if this technique could be a viable processing technology for the extraction of squalene from olive oil pomace. The effects of different solvents and mixtures of solvent, extraction temperature and extraction time were also evaluated for their influence on yield of squalene. Squalene in the olive biomass extracts were quantified by liquid chromatography with UV absorbance and fluorescence detection. In addition, the proposed method was used to determine the content of a-tocopherol in the olive biomass. 

Smoke from forest fires may be collected by various means for subsequent laboratory analysis. The most applicable approach is to trap emissions from biomass burning on absorbent material. The absorbent material is then either solvent-extracted for GC analysis or directly desorbed onto a GC. For example, smoke is pulled with an air pump at a rate of 10-50mLmin through triple-layer glass cartridges with separate... 

Solvent extraction is widely used during early purification of fermentation-derived products and, indeed, of all natural product matrices for initial and intermediate purification prior to final purification by chromatography, crystallization, or precipitation. Solvent extraction provides the ease of liquid handling, the potential for high-throughput operation, and the potential for adaptation to continuous operation. Both water-miscible and immiscible solvents are used for extracting compoimds from the biomass. Frequently, multiple approaches can be employed to purify a fermentation-derived product. Wildfeuer (11) describes many possible approaches for purification of the antibiotic cephalosporin C. 

The second limitation of Py-GC-MS is that the complex pyrolysate was not just pyrolysis products it consisted of evaporation and combustion products of HS. ° It was reported that free compounds, e.g., alkanes, and fatty acids in HS macromolecules evaporated quickly under pyrolysis, and stmctural units split off through burning in the presence of oxygen and can be further incorporated into HS. For example, lipids, e.g., alkanes, fatty acids, dicarboxylic acids, and ketones were often found as free or solvent-extractable compounds in soils and soil HS. These compounds can be synthesized by microorganisms and plants, and can occur upon combustion of fossil fuels and biomasses. Alkylfurans and methoxylated phenols were considered pyrolysis products of... 

HS and combustion products of biomasses, and alkylbenzenes and thiophenes can be both evaporation/pyrolysis products from humic substances. At present, solvent extraction and low temperature desorption followed by TMAH Py-GC-MS have been proposed to distinguish combustion, evaporation and pyrolysis products in the pyrolysis. ... 

Extraction of natural materials in order to produce extracts with useful flavor, fragrance, nutritional and other pharmacological properties is a centuries old practice. Traditionally, such extracts are isolated from the relevant biomass (flowers, roots, peel, leaves etc.) using a variety of processes ranging from steam distillation through solvent extraction to simple mechanical expression. Many of these initial materials have been subjected to further refinement steps in order to produce a finished product of acceptable quality. 

NOD 98] Noda L, Solvent extraction of polyhydroxy-atkanoates from biomass facditated by the use of marginal nonsolvent. Patent US5821299,1998. 

VOCs are mainly hydrocarbons (2.73 Mt in 1997 in the UK) and the most abundant is methane (50% from landfills, 30% from animals, and rest from gas extraction, biomass burning) while non-methane VOC in 1997 in the UK (2.13 Mt in the UK) are mainly emitted from vehicles (40%), from solvents in paints (30%), etc., which is composed of some 200 different hydrocarbons such as benzene and toluene [34],... 

In 2000 and 2001 we tried to use the same proportions of solvents to biomass as were used in 1999. In 2002, extracts of roots and tops were partitioned between hexane and aqueous methanol, as shown in Figure 1. In 2003, we tested isolated and synthesized single compounds in different concentrations. 

The ideal HMF production process would use raw biomass as its feedstock, without the necessity for extensive drying or pretreatment (apart fi om mechanical reduction to particle sizes which do not suffer mass transfer limitations). Reactions would proceed in high yield over short time scales under mild conditimis in inexpensive media and use simple, non-foulable catalysts. The HMF product would be isolated without recourse to distillation or protracted solvent extraction, and all materials would be easily recyclable. Except for product yield, none of these objectives has currently been met in such a way as to be reducible to practice on an industrial scale. In the end, it is a matter of economics. When the dust settles, only the most competitive, industrially viable processes will be left standing, and the rest will be consigned to history. 

There are several PHA extraction methods found in the literature (Figure 6.1). Solvent extraction is the oldest and most commonly used method to extract PHA from the lyophilised biomass and has been used since the discovery of PHA by Lemoigne [9]. Typically, halogenated solvents, such as chloroform, dichloromethane and polychlorinated ethane, are used in the extraction of PHA [10,11]. These solvents act by weakening the cell membrane and subsequently dissolve the PHA. On a laboratory scale, the PHA-containing... 

Garves reported formation of insoluble humic residue at the higher temperatures (P). In our work, the acid-catalyzed reactions of ethanol with seed hulls and with chaff or straw waste at 200 C produced a charcoal product with modest surface areas (//). A significant part (20%-30%) of the cellulose is carbonized to charcoal, which is easily removed by filtration. Flash distillation of the excess alcohol and solvent extraction of the levulinate ester leaves a resinous product consisting mainly of the lignin component of the biomass. Thus multiple marketable products are available from processing waste biomass with the acidic alcohols. 

Noda (1999) Films and absorbent articles comprising a biodegradable polyhydroxyatkanoate comprising 3-hydroxybutyrate and 3-hydroxyhexanoate comonomer units. US Patent 5,990,271 Noda I (2005) Plastic articles digestible by hot alkaline treatment. US Patent 6,872,802 B2 Noda I, Schechtman LA (1999) Solvent extraction of polyhydroxyalkanoates from biomass. US Patent 5,942,597... 

Bio-oil, a kind of biofuel, could be obtained by flash pyrolysis of biomass. Because bio-oil is a type of complex mixture, some researches about bio-oil separation have been conducted in the recent years. Xianwei Zheng et al. have successfully separated flash pyrolysis oil into four kinds of substances by united extraction and distillation. Garcia-Perez et al. have provided an efficient separation method by using five kinds of solvent extraction, and bio-oil was separated into six kinds of substances. 

---