Carbohydrate Polymers 84 (2011) 96–102 Contents lists available at ScienceDirect Carbohydrate Polymers journal homepage: www.elsevier.com/locate/carbpol Structural characterization of bacterial cellulose produced by Gluconacetobacter swingsii sp. from Colombian agroindustrial wastes Cristina Castro a,1 , Robin Zuluaga b,∗ , Jean-Luc Putaux c , Gloria Caro a ,I˜ naki Mondragon d , Piedad Ga ˜ nán a a School of Engineering, Chemical Engineering Program, New Materials Research Group, Pontificia Bolivariana University, Circular 1 # 70-01, Medellín, Colombia b School of Engineering, Agro-Industrial Engineering Program, New Materials Research Group, Pontificia Bolivariana University, Circular 1 # 70-01, Medellín, Colombia c Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), BP 53, F-38041 Grenoble cedex 9, France (affiliated with Université Joseph Fourier and member of the Institut de Chimie Moléculaire de Grenoble) d “Materials + Technologies” Group, Chemical & Environmental Engineering Department, Polytechnic School, Universidad del País Vasco/Euskal Herriko Unibertsitatea, Pza. Europa, 1, 20018 Donostia – San Sebastián, Spain article info Article history: Received 20 September 2010 Received in revised form 23 October 2010 Accepted 27 October 2010 Available online 4 November 2010 Keywords: Acetobacter xylinum Bacterial cellulose Agroindustrial residues Crystal structure abstract Bacterial cellulose microfibrils from non-conventional sources were produced by Gluconacetobacter swingsii sp. Agroindustrial residues such as pineapple peel juice and sugar cane juice were used as culture media. Hestrin and Schramm’s medium was used as a reference. The production of bacterial cellulose from pineapple peel juice (2.8 g/L) was higher than that produced from Hestrin and Schramm’s medium (2.1 g/L). The carbon and nitrogen resources in pineapple peel and sugar cane juice were sufficient for the microorganism development. Ribbon-like microfibrils with a width of 20–70 nm were observed in all media. Changes in crystallinity and mass fraction of the I  allomorph were observed. The aggregation of cellulose chains into microfibrils was slightly hindered by other polysaccharides in the agroindustrial waste that adhered to the surface of the subfibrils. In conclusion, agroindustrial residues can be used as a culture medium to produce bacterial cellulose with low cost for large-scale industrial production. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction Cellulose, the most abundant biopolymer in Nature, can be synthesized by plants, some animals and a large number of microorganisms, as is the case with Gluconacetobacter (formerly Acetobacter)(Brown, 1886a,b). This is a gram-negative bacterium, strictly aerobic, capable of producing cellulose extracellularly at temperatures between 25 and 30 ◦ C and pH from 3 to 7 (Bielecki, Krystynowicz, Turkiewicz, & Kalinowska, 2005; Iguchi, Yamanaka, & Budhiono, 2000), using glucose, fructose, sucrose, mannitol, among others, as carbon sources (Ramanaka, Tomar, & Singh, 2000; Heo & Son, 2002). The bacteria synthesize cellulose as a primary metabolite. This synthesis mechanism helps the aerobic bacteria to move to the oxygen-rich surface. Moreover, the cellulose pelli- cle is produced to protect the cells from ultraviolet light and retain moisture (Klemm, Shumann, Udhardt, & Marsch, 2001). Bacterial cellulose is synthesized in three stages. In the first stage, glucose molecules are polymerized (formation of -1,4- glucosidic linkages) between the outer and cytoplasm membranes, ∗ Corresponding author. Tel.: +57 4 3544532; fax: +57 4 3544532. E-mail addresses: cristina.castro@upb.edu.co (C. Castro), robin.zuluaga@upb.edu.co (R. Zuluaga). 1 Tel.: +57 4 3544532; fax: +57 4 35445432. forming cellulose changes. 10–15 parallel chains form a 1.5 nm- wide protofibril. In a second step, several protofibrils are assembled into 2–4 nm wide microfibrils, and, in a third step a bundle of microfibrils are assembled into a 20–100 nm-wide ribbon. A matrix of interwoven ribbons constitutes the bacterial cellulose pellicle (Iguchi et al., 2000; Klemm et al., 2001). The formation of the pelli- cle can be modified by strong aeration during agitated cultures or by the presence of certain substances that can affect the supramolec- ular organization of microfibrils by disrupting the formation of hydrogen bonds between cellulose chains (Bootten, Harris, Melton, & Newman, 2008; Hirai, Tsuji, Yamamoto, & Horii, 1998; Tokoh, Takabe, Fujita, & Saiki, 1998; Tokoh, Takabe, Sujiyama, & Fujita, 2002; Watanabe, Tabuchi, Moringa, & Yoshinaga, 1998; Whitney, Brigham, Darke, Reid, & Gidley, 1998; Yamamoto & Horii, 1994, 1996). In terms of chemical structure, bacterial cellulose is identical to that produced by plants. However, it exhibits higher crys- tallinity, water-holding capacity, mechanical strength and purity. It contains no lignin, hemicellulose or other natural components. These features make it an interesting raw material for applications as nutritional component (Bielecki et al., 2005), artificial skin (Fontana et al., 1990), composite reinforcement, electronic paper (Jonas & Farah, 1998), flexible display screens (Nakagaito, Nogi, & Yano, 2010) and in traditional applications where plant cellulose is used. However, due to the high cost of carbon sources for 0144-8617/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbpol.2010.10.072