Dissolution and Regeneration of the Produced Nano Bacterial Cellulose of Food Industries Wastewaters by a Cost-Benefit Method

Abstract

This paper applied a simple and cost-benefit method for the production of regenerated bacterial cellulose. The inexpensive production of cellulose with complex media derived from wastewater from food industries such as molasses adds a lot of contaminants to the produced bacterial cellulose, which puts a lot of challenges in cellulose purification. Therefore, the present study aimed to develop an inexpensive strategy for the complete dissolution of the very dirty cellulose produced from the low-cost medium containing molasses and corn steep liquor, and the reconstruction of pure bacterial cellulose that can be used for all types of cellulose. The bacterial cellulose was produced by Gluconacetobacter xylinus BRP2001 in an effective and inexpensive culture media including a mixture of molasses and corn steep liquor, then cuprammonium rayon method as a cost effective approach was modified for quick and complete dissolution of the bacterial cellulose. The main parameters in cuprammonium method such as the value of sodium hydroxide and copper sulfate, the water removal method and dissolution process were optimized by irregular fraction design. In addition to cost, the time of dissolution process of bacterial cellulose was reduced to less than 1 hour which is unprecedented in comparison with other conventional methods. Regeneration of bacterial cellulose for the fabrication of novel regenerated bacterial cellulose was carried out using dilute sulfuric acid. Under the optimum rayon method comprising 3 wt% NaOH/ 6 wt% copper sulfate solution, the diameter of the nanofibers of bacterial cellulose and regenerated bacterial cellulose ranged between 20-80 nm and 60-120 nm, respectively. Also, the crystal sizes of bacterial and regenerated bacterial cellulose were estimated at about 59.74nm and 6.13nm and the crystallinity indexes of bacterial cellulose and regenerated bacterial cellulose were calculated as 89% and 64%, respectively. The mechanical modulus and crystallinity of regenerated bacterial cellulose were significantly reduced because of the disruption of the hydrogen bond.

Keywords

• nano bacterial cellulose
• regenerated bacterial cellulose
• cellulose properties
• cuprammonium rayon