Abstract:
The objective of this research was to compare the coagulation of natural rubber latex by acetic acid and bacteria in liquid broth. Both processes were evaluated by considering the physical properties of dry rubber obtained. Raw materials were fresh field latex and LA latex concentrate. Coagulation of latex concentrate was carried out to pave way for further investigation of using bacteria in dipping process Bacillus subtilis TISTR25 was used to reduce protein content in rubber, determined by its nitrogen content; the broth was either a minimum medium or a complex medium. Acetobacter aceti TISTR102 was prepared with different age and medium for used as a coagulant in comparison with acetic acid. Bacterial coagulant was applied together with the B. subtilis broth. When applied, the properties of dry rubber sheet i.e. ash, nitrogen, dirt, volatile matter, initial plasticity, plasticity retention index and Mooney viscosity were better than the sheet obtained by using acetic acid. B. subtilis in both media reduced nitrogen content from 0.37 to 0.21 and 0.25%w respectively. When latex concentrate was used the rubber sheet also showed better properties than that obtained by using acetic acid.