Fig. 1

a TLC of polyamide waste. TLC plates showing components of solubilised oligomer waste before and after hydrolysis using acid (2 M sulphuric acid at 130 °C). The chromatogram was developed using the solvent system composed of n-propanol: ethyl acetate: ammonia: water (6:1:1:3) to resolve the linear components which were detected using ninhydrin reagent. Alternately the chromatogram was developed using the solvent system composed of n-butanol: acetic acid: water (12:3:5) to resolve the cyclic components which were detected using Dragendorff’s reagent. Lanes 1, 2, 3 show linear components after acid hydrolysis at 4.5 h, 0.5 h, 0 h. Lane 4: standard 6-ACA. 0 h is the unhydrolysed sample showing ACA, linear dimer, linear trimer; Rf 0.6, 0.81, 0.89 respectively. Lanes 5, 6, 7 show cyclic components after acid hydrolysis at 4.5 h, 0.5 h, 0 h. Lane 8: standard caprolactam. 0 h is the unhydrolysed sample showing caprolactam, cyclic dimer, cyclic trimer, cyclic tetramer, cyclic pentamer; Rf 0.79, 0.73, 0,68, 0.64, 0.56 respectively. b TLC of polyamide waste treated using bacteria*. *Solubilised oligomer waste was treated with a mixture of Arthrobacter citreus, Rhodococcus rhodochrous, Bacillus sphaericus and Alcaligenes faecalis. Lanes 1, 2, 3 showing linear components: 0 h, 24 h, 48 h after incubation; 48 h sample shows absence of 6-ACA. Lanes 4, 5, 6 showing cyclic components: 0 h, 24 h, 48 h after incubation; 48 h sample shows absence of caprolactam