The Production of Bacterial Cellulose from Organic Low-Grade Rice

Yuwarat Photphisutthiphong^1*, Savitri Vatanyoopaisarn²

¹Department of Environmental Technology, Faculty of Science and Technology, Suan Dusit University, Bangkok, Thailand.

²Department of Agro-Industrial, Food and Environmental Technology, Faculty of Applied Science, King Mongkut’s University of Technology North Bangkok, Bangkok, Thailand.

Corresponding Author Email: muayyai@hotmail.com

Bacterial cellulose (BC) is a dietary fiber produced from some strains of acetic acid bacteria. Coconut water is the major substrate to ferment the bacterial cellulose for the food industry. However, the area of plantation is limited in a specific region, so the shortage of raw material occasionally occurred from the natural disaster. In contrast, rice cultivation is a major crop, millions of tons produced yearly. The rice mill industry also yields 2.5% of the underspecification grains. This research demonstrated the use of organic low-grade rice strains (Riceberry rice, brown jasmine rice, jasmine rice, red jasmine rice, and Homnil rice) as substrates for BC production. The study showed that the ground rice powder required enzymatic hydrolysis of 25 µl of alpha-amylase 10%(v/v) at 90ºC for 30 min, and followed by 50 µl of glucoamylase 20% (v/v) at 60ºC for 90 minutes to completely convert starch to reducing sugar. Such enzymatic hydrolysate was in liquid form with TSS of 8°Brix. The cellulose production by Komagatacibacter nataicola TISTR 975 was carried out using the saccharified rice medium containing 0.7% (NH4)2SO4, initial pH 5.0 with 15% inoculum. Incubation at a static state for 15 days yielded the maximum weight of bacterial cellulose at 401.717 ±5.383 g/l when brown jasmine rice was the substrate. For jasmine rice, red jasmine rice, Homnil, and Riceberry rice, the weights of cellulose were 367.294 ±3.986, 335.244 ±4.707, 321.233 ±4.279 and 308.100 ±2.809g/l, respectively. Sensory scores of the cellulose product showed that the cellulose in the syrup was highly accepted. Different cubic sizes and quantities were prepared and mixed in 3 food products. A rice beverage the size of 0.5×0.5×0.5 cm3 at 15 % (w0v) received the highest attribute scores. Whereas in soy yogurt, 1.0×1.0×1.0 cm3 at 10% (w/v) the mix of cellulose was the most preferable. The herbal drink assorted with bacterial cellulose of 0.25×0.25×0.25 cm3 at 20% (w/v) had the highest scores out of 30 panelists.

α-Amylase; Bacterial Cellulose; Glucoamylase; Komagatacibacter nataicola TISTR 975; Organic Broken Rice

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