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Sugarcane straw (SCS) lignin is extracted by SO 2 -Alcohol-Water (SAW) fractionation (155 °C, 1 h) using methanol, ethanol or isopropanol as pulping solvent (SO 2 /Alcohol/Water = 12/44/44 wt%). The SAW fractionation removes 90–95% lignin from SCS of which only 30–45% is isolated as precipitated lignin after solvent evaporation. The precipitated and pulp residual lignin (5–10%) are analyzed for their degree of sulfonation (S/C9) while precipitated lignin is further analyzed in terms of molecular weight distribution (MWD) and alkoxylation reactions. Similar S/C9 values for methanol, ethanol and isopropanol lignin show that the degree of sulfonation is independent of fractionation solvent. However, the sulfonated lignin is comparatively less soluble in the methanol-based liquor compared to the corresponding lignins in the ethanol- and isopropanol-based liquors. The mass average molecular weight, M w , is highest for isopropanol lignin (∼3800) while the numbers for methanol and ethanol lignins are comparatively smaller but nearly equal in magnitude (∼3000). Alkoxyl groups and nuclear magnetic resonance (NMR) analyses are performed to interpret the differences in lignin M w and alkoxylation reactions. Different ether and ester type linkages are identified in NMR spectra confirming lignin alkoxylation. Lignin carbohydrate complexes (LCC) are also found in NMR spectra confirming that some of the detected carbohydrates are covalently bound to lignin. [ABSTRACT FROM AUTHOR]

Wheat straw was pretreated at 150 °C for 100 min at a liquor-to-straw ratio of 6 L/kg (oven dry basis) straw using aqueous formic acid (FA) concentrations ranging from 0 to 15 g/L. The results showed excellent sugar and lignin mass balances for pretreatment, and precipitated lignin in the hydrolysate obtained at 15 g/L of FA decreased to 0.31 g/100 g straw compared to autohydrolysis (no FA) of 0.94 g/100 g straw. The average molecular weight of precipitated lignin decreased from 1970 g/mole for autohydrolysis to 710 g/mole at 15 g/L of FA. The monomeric sugar yield during pretreatment improved from 3.83 g/100 g for autohydrolysis to 23.5 g/100 g at 15 g/L FA. [ABSTRACT FROM AUTHOR]

Abstract: The present study proposes the use of market rejected and waste vegetables as a supplement for improved acetone–ethanol–butanol (ABE) solvent production. In the present study, three different perishable vegetables were evaluated as supplements for ABE fermentation. These vegetables were found to stimulate the solvent production at as low as 1% (w/v) concentration. The supplementation showed improved production of solvents using 4-fold diluted SO2–ethanol–water (SEW) spent liquor supplemented with 25g/l glucose as a substrate. The maximum total solvent production obtained with 5% (w/v) supplementation of carrot, cabbage and tomato was 9.96g/l, 10.49g/l and 10.65g/l, respectively as compared to the control value of 7.43g/l. The applicability of vegetables was successfully evaluated as a complex medium for solvent production. [Copyright &y& Elsevier]