Carboxymethyl Bacterial Cellulose from Nata de Coco: Effects of NaOH

Abstract

Bacterial cellulose from nata de coco was prepared from the fermentation of coconut juice with Acetobacter xylinum for 10 days at room temperature under sterile conditions. Carboxymethyl cellulose (CMC) was transformed from the bacterial cellulose from the nata de coco by carboxymethylation using different concentrations of sodium hydroxide (NaOH) and monochloroacetic acid (MCA) in an isopropyl (IPA) medium. The effects of various NaOH concentrations on the degree of substitution (DS), chemical structure, viscosity, color, crystallinity, morphology and the thermal properties of carboxymethyl bacterial cellulose powder from nata de coco (CMCn) were evaluated. In the carboxymethylation process, the optimal condition resulted from NaOH amount of 30 g/100 mL, as this provided the highest DS value (0.92). The crystallinity of CMCn declined after synthesis but seemed to be the same in each condition. The mechanical properties (tensile strength and percentage of elongation at break), water vapor permeability (WVP) and morphology of CMCn films obtained from CMCn synthesis using different NaOH concentrations were investigated. The tensile strength of CMCn film synthesized with a NaOH concentration of 30 g/100 mL increased, however it declined when the amount of NaOH concentration was too high. This result correlated with the DS value. The highest percent elongation at break was obtained from CMCn films synthesized with 50 g/100 mL NaOH, whereas the elongation at break decreased when NaOH concentration increased to 60 g/100 mL.

Effect of Monochloroacetic Acid on Properties of Carboxymethyl Bacterial Cellulose Powder and Film from Nata de Coco

“…A maximum DS of 0.83 was obtained with 24 g/15 g cellulose of MCA. At high levels of MCA, the MCA molecules were more available and substitution in molecules of cellulose was easier [16,20]. A similar result was reported regarding the DS value of CMC from sugar beet pulp [16], banana pseudo-stems [9], Mimosa pigra peels [6], durian rinds [12], and asparagus stalk end [14].…”

“…However, plant cellulose causes deforestation and environmental problems. Therefore, many research projects have reported that CMC can be synthesized from agricultural wastes such as sugar beet pulp [16], cavendish banana pseudo-stems [9], sago waste [17], papaya peels [18], Mimosa pigra peels [6], durian rinds [12], mulberry paper [19], asparagus stalk end [14], and bacterial cellulose [20].…”

Recent Developments of Carboxymethyl Cellulose

“…For example, depending on the varying concentration of NaOH, V. Pushpamalar (2006) [141] reported a range of DS of 0.51-0.82 (for sago waste) [5]; 0.56-0.87 (for durian rind) [9]; 0.14-1.76 (for water hyacinth) [140]; 0.1-2.41 (for corn husk) [119]; and 0.15-0.93 (for African star apple seed shell) [141], respectively. A higher DS value was determined mostly against 30% NaOH [116,119,141] and negligible at 25% and 10% NaOH [5,140]. Interestingly, under or above the 30% NaOH, the DS value often declines due to low reaction rate and polymer degradation [116].…”

“…), and property-based applications of aqueous Na-CMC (or H-CMC). Because the high or low viscosity of the applied medium is maintained with increasing or decreasing CMC concentration, respectively; on the other hand, the viscosity property of CMC also depends on or is influenced by the source parameters (like cellulose particle size, molecular weight, and DS) and synthesis conditions (concentration of NaOH, reaction temperature, and pH of solution) of CMC from cellulose, as depicted in the Supplementary Materials (Figure S3) [10,[116][117][118][119].…”

Characterization of Chitosan Film Incorporated with Curcumin Extract

“…The water-soluble matter (SM) of the films was determined in triplicate as described by Rachtanapun et al [22], with slight modifications. Film samples (2 cm × 2 cm) were dried at 105 • C for 24 h, kept in desiccators for 24 h, weighed at 0.2000 g initial dry weight (W i ), and then immersed in 50 mL of distilled water for 24 h at 25 • C and stirred at 68 rpm.…”