Category Archives: Biomass Conversion

Enzymatic Hydrolysis

Enzymatic hydrolysis has an upper edge over acid hydrolysis to produce sugars for alcohol fermentations. Enzymes are naturally occurring plant proteins that cause certain chemical reactions to occur. There are two technological developments: enzymatic and direct microbial conversion methods. The chemical pretreatment of the cellulosic biomass is necessary before enzymatic hydrolysis. The first appli­cation of enzymatic hydrolysis was used in […]

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Supercritical Extraction and Crystallization

Klemola and Tuovinen [170] have developed the technology of supercritical extraction applied to the vanillin production process in order to replace extraction with organic solvents and reextraction to aqueous solution. After the air oxidation of lignin under alkaline conditions, the resulting solution is submitted to a supercritical carbon dioxide flow in the range of operation 75-400 bars and 303-373 K […]

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Pre-treatment of Mixed Culture

A practical source of mixed cultures can easily be obtained from industrial wastewater treatment plants since they are non-sterile. However, this provides a very complex microbial community which includes together hydrogen producing and hydrogen consuming bacteria. Therefore, it is important to select a proper pretreatment method that will adequately select for the hydrogen producers and reduce or eliminate the hydrogen […]

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Characteristics

The weight-average molecular weight (Mw) reported for softwood lignosulfonates are in the range of 10-60 kDa with high polidispersity [23, 60, 61]. These lignins present, in general, higher molecular weight and have fewer hydroxylphenolic (OHph) groups than kraft lignin [20, 23] (as depicted in Table 12.2) which is in accordance with low rate of cleavage of ether linkages of lignin […]

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Metal Hyper-Accumulator Plants

They take up significant amounts of metal from contaminated soil but their low biomass production tends to limit their phytoextraction ability. As these plants have natural ability to extract metal ions, so it is known as natural phytoex­traction. Hyper-accumulating plants have natural ability to extract high amounts of metals from soil, have efficient mechanism to translocate metals from roots to […]

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Ethanol Fractionation

Ethanol has been used to split lignocelluloses into their components to study the structure of lignin, and used as a pulping agent in organosolv pulping. Recently, ethanol fractionation is becoming a major fractionation process among the organosolv fractionation processes for pretreatment lignocellulosic material to produce bioethanol. Generally, ethanol fractionation process is carried out under elevated temperatures without or with the […]

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Effect of Initial Concentration of NaOH (CNaOH)

Figure 12.9b reveals the importance of the OH — on the yield of the process of lignin oxidation at the conditions of this study: a considerable increment of vanillin is achieved by increasing NaOH concentration. The reasons for this impact on yield were already stated in Sect. 4.4.1 (regarding postulate chemical mechanism of oxidation). However, other considerations should be noted: […]

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