Enzymatic Production of Xylooligosaccharides from Cotton Stalks

Abstract

Xylooligosaccharide (XO) production was performed from xylan, which was obtained by alkali extraction from cotton stalk, a major agricultural waste in Turkey. Enzymatic hydrolysis was selected to prevent byproduct formation such as xylose and furfural. Xylan was hydrolyzed using a commercial xylanase preparation, and the effects of pH, temperature, hydrolysis period, and substrate and enzyme concentrations on the XO yield and degree of polymerization (DP) were investigated. Cotton stalk contains about 21% xylan, the composition of which was determined as 84% xylose, 7% glucose, and 9% uronic acid after complete acid hydrolysis. XOs in the DP range of 2-7 (X6 approximately X5>X2>X3) were obtained with minor quantities of xylose in all of the hydrolysis conditions used. Although after 24 h of hydrolysis at 40 degrees C, the yield was about 53%, the XO production rate leveled off after 8-24 h of hydrolysis. XO yield was affected by all of the parameters investigated; however, none of them affected the DP of the end product significantly, except the hydrolysis period. Enzyme hydrolysis was maintained by the addition of fresh substrate after 72 h of hydrolysis, indicating the persistence of enzyme activity. The optimal hydrolysis conditions were determined as 40 degrees C, pH 5.4, and 2% xylan. The obtained product was fractionated via ultrafiltration by using 10, 3, and 1 kDa membranes. Complete removal of xylanase and unhydrolyzed xylan was achieved without losing any oligosaccharides having DP 5 or smaller by 10 kDa membrane. After a two-step membrane processing, a permeate containing mostly oligosaccharides was obtained.

Value addition of orange fruit wastes in the enzymatic production of xylooligosaccharides

“…Concentration of reducing sugar = Extrapolation on the X axis x Dilution factor The graph was plotted using MS Excel 2007 and the R value was measured (Somogyi, 1952;Akpinar et al, 2007). For each different concentration of standards and samples, ANOVA was analyzed separately using MS Figure 2 shows the xylose as standard (1 mg/100 ml = 0.001% carried out) and the concentration of reducing sugar was found to be 3.58E-05 and 3.54E-05 in 2 and 4 ml respectively for 12% unknown sample solution.…”

“…The quantification of sample XOS was based upon comparison of average peak areas compared with the standards XOS (X1-X5= (xylose, xylobiose, xylotriose, xylotetrose and xylopentose). The quantification was expressed in ng/ml and converted to mg/ml for further analysis (Samanta et al, 2012b;Akpinar et al, 2007). All standards were provided and analysis was performed at National Institute of Animal Nutrition and Physiology Bangalore.…”

XYLOOLIGOSACCHARIDES PRODUCTION FROM OIL PALM FROND BY Trichoderma longibrachiatum XYLANASE

“…XOs are sugar oligomers made up of xylose unit. XOs can be used as ingredients of functional foods, cosmetics, pharmaceuticals or agricultural products [2] Enzymatic method is more preferable to produce XOs compared to other methods, because it does not produce undesirable component or high amount of monomers and does not require special equipment [3]. Enzymatic production of xylooligosaccharides performed by xylanase having high endoxylanase and low β-xylosidase activity besides present of others side group enzyme removal include α-arabinofuranosidases, acetylxylan esterase, and α-glucuronidase [4].…”

“…Enzymatic production of xylooligosaccharides performed by xylanase having high endoxylanase and low β-xylosidase activity besides present of others side group enzyme removal include α-arabinofuranosidases, acetylxylan esterase, and α-glucuronidase [4]. Membrane separations, such as ultrafiltration and nanofiltration have been shown to be very promising methods for refining and concentrating several oligosaccharides [3]. Membrane technologies have been applied successfully in conjugation with enzymatic hydrolysis following steam hydrolysis for processing XOs.…”

Optimisation of solid-state fermentation of Aspergillus niger JL-15 for xylanase production and xylooligosaccharides preparation

“…Xylanases have attracted considerable research interest in recent years mainly due to their potential application in food, animal feed, and paper and pulp industries. the production of xyloses by enzymatic hydrolysis of xylan from xylan-rich materials (Vazquez et al 2000;Yang et al 2005;Moure et al 2006;Yuan et al 2006;Akpinar et al 2007). …”