Bioprocess BiosystEng
Biological synthesis of Au nanoparticles using liquefied mash of cassava starch and their functionalization for enhanced hydrolysis of xylan by recombinant xylanase
Sumei Zeng1, 2 • Liangwei Du1, 3 • Meiying Huang1, 3 • Jia-Xun Feng1, 2
1 State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, 100 Daxue Road, Nanning530004, Guangxi, People’s Republic of China
2 College of Life Scienceand Technology, Guangxi University, 100 Daxue Road, Nanning530004, Guangxi,People’s Republic of China
3 College of Chemistry and Chemical Engineering, Guangxi University,100 Daxue Road, Nanning530004, Guangxi,People’s Republic of China
Jia-Xun Feng
Liangwei Du
Online Resource1
Preparation of AuNPs by commercially available sugars
Materials andmethods
We designed a series of experiments to confirm that the reduction of Au3+ to Au0 is mainly due to the constituent sugars in liquefied cassava mash. Commercially available sugars[(a) 1.2 mmolglucose, (b) 1.2 mmol maltose, (c) 1.2 mmolmaltotriose, (d) 0.6 mmol glucose + 0.6 mmol maltose, (e) 0.6 mmol glucose + 0.6 mmolmaltotriose, (f) 0.6 mmol maltose + 0.6 mmolmaltotriose, (g) 0.4 mmol glucose + 0.4 mmol maltose + 0.4 mmolmaltotriose] with 10 µL of 0.1 M aqueous HAuCl4 was added to 1.5 mL deionized water. The reaction mixtures were agitated in the photochemical reaction instrumentwith a 500 W xenon lamp at 28 ºC. The reaction mixtures were studied by UV–Vis spectroscopy after the reaction was completed.
Results and discussion
It has been previously reported that the liquefied cassava mash contained various kinds of oligosaccharides[1]. HPLC analyses of the liquefied cassava mash used in this study showedthatthe mash containedglucose, maltose, and maltotriose at 0.0433, 0.0266, and 0.0516 mmol/mL, respectively. Fig. 1 shows the UV–Vis spectra of AuNPs synthesized by commercially available glucose, maltose and maltotriose. It has intense SPR peaks atca. 540 nm characteristic of AuNPs similar to the UV–Vis spectra of AuNPs synthesized by liquefied cassava mash (Fig. 1). This indicates that Au3+was reduced to AuNPs by glucose, maltose and maltotriose under the irradiation of xenon lamp. Kumar et al. [2] demonstrated that AuNPs synthesized by glucose were triangles, hexagons and other irregular shapes. The reduction of Ag+ to 10–80 nm Ag nanoparticles by maltose has also been reported[3].
Fig. 1 UV–Vis spectra of AuNPs synthesized by commercially available sugars: (a) glucose, (b) maltose, (c) maltotriose, (d) glucose + maltose, (e) glucose + maltotriose, (f) maltose + maltotriose, and (g) glucose + maltose + maltotriose.
References
1.Maeda H, Kajiwara S, Araujo NQ (1982) The separation of solids from the liquefied mash of cassava tuber and continuous saccharification by immobilized glucoamylase. Eur J Appl Microbiol Biotechnol 16: 92–98
2.Kumar CG, Mamidyala SK, Sreedhar B, Reddy BV (2011) Synthesis and characterization of gold glyconanoparticles functionalized with sugars of sweet sorghumsyrup. Biotechnol Progr 27: 1455–1463
3.Filippo E, Serra A, Buccolieri A, Manno D (2010) Green synthesis of silver nanoparticles with sucrose and maltose: Morphological and structural characterization. J Non-Cryst Solids 356: 344–350