2017 Volume 50 Issue 11 Pages 857-861
Nano Microbial Cellulose (MC) has many applications in producing biocomposites such as biodegradability, lightness, purity and high specific area. Therefore, many studies focus on improving characteristic and enhancing the amount of production. In this study, mechanical properties of MC are evaluated by investigating the effect of some medium condition parameters like surface area to volume ratio, type of strain, kind of nutrient and cultivation time. Two different kinds of strains such as Acetobacter xylinum BPR2001 and Acetobacter xylinum AT have been cultivated in an HS and molasses mixture culture medium for 10 and 20 d with a surface area to volume ratio of 0.25 and 0.75, and the mechanical properties of specimens were assessed. According to the obtained results, the tensile strength of produced MC from HS culture medium with a 0.25 (20-d) surface area to volume ratio by Acetobacter xylinum BPR2001 is 58% more than Acetobacter xylinum AT, and its tensile Modulus is also improved by 63%. The results indicated that increasing the tensile strength and tensile Modulus is directly related to the time of growth. In addition, the tensile strength and tensile Modulus decrease considerably whenever the surface area to volume ratio increases. The 20-d MC produced by Acetobacter xylinum AT in a 0.25 surface area to volume ratio represents higher tensile strength (2.5 times) and tensile modules (2.2 times) than the other. MC produced in molasses culture medium shows 12% and 36% growth in tensile strength and tensile modulus, respectively. Therefore, MC produced by Acetobacter xylinumBPR2001 with a 0.25 surface area to volume ratio is an adequate alternative which can be applied for biocomposite.
