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Acetobacter aceti MTCC 2623 was studied as an alternative microbial source for bacterial cellulose (BC) production. Effect of media components on cell growth rate, BC production and cellulose characteristics were studied. FTIR results showed significant variations in cellulose characteristics produced by A. aceti in different media. Results have shown the role of fermentation time on crystallinity ratio of BC in different media. Further, effect of six different media components on cell growth and BC production was studied using fractional factorial design. Citric acid was found to be the most significant media component for cell growth rate (95% confidence level, R(2)=0.95). However, direct role of these parameters on cellulose production was not established (p-value>0.05).

Bacterial cellulose (BC) exhibits unique properties including high mechanical strength and high crystallinity. Improvement in the mechanical properties of BC is sought for many applications ranging from food to structural composites to biomedical materials. In this study, different additives including carboxymethyl cellulose (CMC), pectin, gelatin, cornstarch, and corn steep liquor were included in the fermentation media to alter the BC produced. Three different concentrations (1%, 3% and 5%) were chosen for each of the additives, with no additive (0%) as the control. The produced BC was then analyzed to determine tensile and compression modulus. Amongst the tested additives, BC produced in media containing 3% (w/v) pectin had the maximum compressive modulus (142kPa), and BC produced in media containing 1% (w/v) gelatin exhibited the maximum tensile modulus (21MPa). Structural characteristics of BC and BC-additive composites were compared using X-Ray diffraction (XRD). The crystal size and crystallinity of BC was reduced when grown in the presence of CMC and gelatin while pectin only decreased the crystallite size. This suggested that CMC and gelatin may be incorporated into the BC fibril structure. The field emission scanning electron microscopy (FESEM) images showed the increased micro-fibril aggregation in BC pellicles grown in the presence of additives to the culture media.

Bacterial cellulose (BC) displays unique properties which imparts it high mechanical strength and high crystallinity. Improvement in the mechanical properties of BC is sought for many applications ranging from structural composites to biomedical materials. In this study effects of pectin, corn steep liquor and a binary system of 1:1 ratio of pectin and corn steep liquor was studied on BC properties, with no additive (0%) being the control. The produced BC was then analyzed to determine tensile and compression modulus, and a significant increase in these value were observed (p

An indigenous Z-scan set up has been fabricated for the study of nonlinear optical properties of solids. Few crystals have been used to verify the performance of the home made system. An automatic scanning is made possible by burning a program to the IC. Although the paper is based on instrumentation, it also summarises for Z-scan set ups commonly used in nonlinear optical studies and their relative advantages. A solid (ruby crystal) and CS2 liquid has been used for parametric studies.