Fig. 3

SEM micrograph of microbial colonization (conventional retting) on jute bark. (a, c, e, g, i) Inner surfaces of jute bark; (b, d, f, h, j) Outer surfaces of jute bark; (a, b) Inner and outer surfaces of fresh jute bark showing fibre boundaries with intact cementing material around them; no microbiological growth was observed. (c, d) Inner and outer surfaces of jute bark on day 3 of the retting period; scattered microbial structures were found on both surfaces. (e, f) Inner and outer surfaces of jute bark on day 5 of the retting period. Minor cracks were found on the outer surface, and microbial growth occurred on both sides of the jute stems. (g, h) Inner and outer surfaces of jute bark on day 7 of the retting period. Microbial mats were visible on the outer side of the stems, and bacterial cells and fungal spores were observed adhering to the inner surface. The outside surface was found to have perforations. (i, j) Inner and outer surfaces of the retted jute fibre. The retting process took 18 days to complete in the case of conventional retting without microbial formulation