A Potential Application of the Mechanical Tensile Strength Test for Indicating Paper Biodegradation

Tensile strength test for paper has been regularly used in measurement of paper quality in the industry. In this study, changes in properties of paper during biodegradation were compared by measurement of the tensile strength cellulose activity. Samples of filter paper and polyethylene coated paper were digested with cellulose degrading Bacillus isolates. Treatment with water was used as a negative control. The paper samples were cut into precise shape according to the standard protocol of mechanical tensile strength test to measure the maximum tensile force. After removing bacterial biomass, reducing sugars were measured as a surrogate for callulase activity in the spent fermentation broth and the paper samples were subjected to the mechanical strength, breaking load and stretch tests. The results showed the amount of stretch in paper was critically reduced over longer contact time in bacterial culture. Changes in the mechanical strength were apparent within 3-7 days of contact time, whereas changes in reducing sugars were observed only after 7-10 days of incubation depending on the paper type. In filter paper samples, more reducing sugars and less mechanical strength indicated increased biodegradation of the cellulose matrix. Overall, the mechanical tensile strength test was deemed an early indicator for paper biodegradation that may have commercial application.