Evaluation of cotton stalk hydrolysate for xylitol production

Sapci, Burcu
Bolukbasi, Ufuk
Yılmaz, Levent
Cotton stalk is a widely distributed and abundant lignocellulosic waste found in Turkey. Because of its rich xylose content, it can be a promising source for the production of xylitol. Xylitol can be produced by chemical or biotechnological methods. Because the biotechnological method is a simple process with great substrate specificity and low energy requirements, it is more of an economic alternative for the xylitol production. This study aimed to use cotton stalk for the production of xylitol with Candida tropicalis Kuen 1022. For this purpose, the combined effects of different oxygen concentration, inoculum level and substrate concentration were investigated to obtain high xylitol yield and volumetric xylitol production rate. Candida tropicalis Kuen 1022 afforded different concentrations of xylitol depending on xylose concentration, inoculum level, and oxygen concentration. The optimum xylose, yeast concentration, and airflow rate for cotton stalk hydrolysate were found as 10.41gL(-1), 0.99gL(-1), and 1.02vvm, respectively, and under these conditions, xylitol yield and volumetric xylitol production rate were obtained as 36% and 0.06gL(-1)hr(-1), respectively. The results of this study show that cotton stalk can serve as a potential renewable source for the production of xylitol.


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Dioctahedral vermiculite occurs in an isolated metagabbro klippe (Kurancali Metagabbro) that belongs to the Central Anatolian Ophiolites from central Turkey. Both the metagabbro and the structurally underlying high-grade metamorphic rocks are intruded by granitic rocks. The Kurancali Metagabbro is characterized by its well-developed compositional layering, and the presence of vermiculitized phlogopite rich layers. Petrographic and mineralogic studies show that the primary mineral phases in the host rock are...
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AKPINAR, ÖZLEM; Erdogan, Kader; Bakir, Ufuk; Yılmaz, Levent (2010-01-01)
Tobacco stalk (TS), a major agricultural waste in the Black Sea region of Turkey, was used for the production of xylooligosaccharides (XOs). It contains about 22 g/100 g xylan whose composition was determined as 93.5 g/100 g xylose, 6.54 g/100 g glucose and 11.2 g/100 g uronic acid after complete acid hydrolysis. XO production was performed by enzymatic and acid hydrolysis of xylan which was obtained by alkali extraction from tobacco stalk. In enzyme hydrolysis, xylan was hydrolyzed using a xylanase prepara...
Enzymatic production of xylooligosaccharides from cotton stalks
Akpinar, Ozlem; Ak, Ozlem; Kavas, Aysegul; Bakir, Ufuk; Yılmaz, Levent (2007-07-11)
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% x...
Antioxidant properties of Salvia absconditiflora extracts and their effects on phase I and phase II gene expressions in HEPG2 cell line
İrtem Kartal, Deniz; Güray, Tülin; Sadi, Gökhan; Department of Biochemistry (2015)
S.absconditiflora is one of the endemic Salvia species grown in Turkey, which is consumed as a herbal tea. Because of the presence of high amounts of vesicles on their leaves, it is very rich in bioactive compounds. S.absconditiflora water and methanol extracts were studied for their antioxidant capacity by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ABTS free radical scavenging assay. Total phenolic and total flavonoid contents were quantified by spectrophotometric methods, HPLC and LC-MS/MS analyses and the ...
Pattern of genetic diversity in Turkey oak (quercus cerris l.) populations
Tümbilen Özer, Yeliz; Kaya, Zeki; Department of Biology (2014)
Quercus cerris L. is a native and widely distributed species in Turkey. It is an important element of Anatolian forests and with other oak species constitute 76.4% of broadleafed forests. However, there is little information on the genetic make-up of Turkish populations. In the current study, the genetic diversity of Q. cerris populations sampled within their natural range is assessed with microsatellite loci (SSRs) polymorphism. Thirteen populations were sampled from seven different locations. Four of thes...
Citation Formats
B. Sapci, Ö. AKPINAR, U. Bolukbasi, and L. Yılmaz, “Evaluation of cotton stalk hydrolysate for xylitol production,” PREPARATIVE BIOCHEMISTRY & BIOTECHNOLOGY, pp. 474–482, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42837.