Khairul Azly Zahan

Potential use of biofibers for functional immobilization of lactobacillus rhamnosus NRRL 442

The present study aimed to characterize the agricultural residues of sugarcane bagasse {SB} and pineapple core {PC} for the use in immobilization of Lactobacillus rhamnosus NRRL 442. Using Standard Official Methods, SB and PC were found to contain approximately equal amount of nutrition content. The nutrition contents found include: 2.7-2.8 % of protein, 9.8-10 % of crude fiber, and 0.3-0.5 % of fat. On the other hand, SB demonstrated relatively higher solution holding capacity of 9.42 ± 2.3 g/g dry size sample than that of 6.04 ± 2.1 g/g dry size sample in PC. Under screening electron microscope, the fiber of SB has a flat and even surface; in contrast, the fiber of PC has a rough and overlapping surface which may promote the attachment or cell holding capacity during the immobilization process. However, the viability tests after cells immobilization have shown that SB provided higher cell survivability of 93.6 % than that of 64.1% in PC. These result highlighted the greater role of solution holding capacity of cellulose in ensuring a better cell survivability after immobilization process. As conclusion, this study showed the near future potentiality of SB and PC as immobilization carriers for Lactobacillus rhamnosus NRRL 442. It may substitutes proportionally of raw materials and be functional feed for ruminant.

Effect of Incubation Temperature on Growth of Acetobacter xylinum 0416 and Bacterial Cellulose Production

The objective of this research was to investigate the effect of incubation temperature towards the growth of Acetobacter xylinum 0416 and the production of bacterial cellulose. Fermentation of A.xylinum 0416 were carried out for 5 days in static condition using Hestrin & Schramm (HS) medium with initial glucose concentration of 4.0% (w/v) and initial pH of 6.4. The incubation temperature were varied at 5°C, 20°C, 25°C, 27°C, 28°C, 30°C, 35°C and 40°C respectively. Results indicated that 28°C served as the best incubation temperature for the growth of A.xylinum 0416 and produced the highest amount of bacterial cellulose with total dried weight of 0.3722 g/l. Meanwhile at incubation temperature of 5°C and 40°C, no significant growth of A.xylinum 0416 and bacterial cellulose were obtained. As a conclusion, incubation temperature plays an important role for the growth of A.xylinum 0416. The best incubation temperature is at 28°C in which the sufficient energy will be provided for bacterial growth thus enhancing the cellulose biosynthetic pathway in order to convert glucose into bacterial cellulose.

Monitoring Initial Glucose Concentration for Optimum pH Control during Fermentation of Microbial Cellulose in Rotary Discs Reactor

The study aimed to investigate the effect of initial glucose concentration on the microbial cellulose production using Acetobacter xylinum in a Rotary Discs Reactor (RDR-2 liter volume). The fermentations were carried out for four days at temperature 28°C, initial pH 6.5, and 9 rpm of rotation speed; meanwhile, the initial glucose concentration was manipulated in the range of 0.5-5.0 % (w/v). The cell growth was stimulated using 1.4% (v/v) ethanol in the fermentation medium. The result indicated that 1% (w/v) of initial glucose concentration provided the highest microbial cellulose yield with total wet weight of 296.1657g/l. The increase of initial glucose concentration resulted to the decrease of microbial cellulose yield and greater pH drop after fermentation. It can be conclude that production of microbial cellulose using RDR could produce relatively much higher microbial cellulose with less amounts of glucose in a shorter fermentation period compared to static fermentation due to more efficient oxygen uptake during rotary movements and homogenous environment for microbial growth.

Development of medical cotton fabrics with Punica granatum L extract finishing for nosocomial infections control

ABSTRACT Transmission of pathogenic microorganisms on textile in the hospital settings may contribute to nosocomial infection. This study was aimed to develop a natural antimicrobial finishing on textile that can prevent transmission of pathogenic microorganisms that meets American Association of Textiles Chemists and Colorists (AATCC) standard. Punica granatum L ethanolic extract was shown to have broad spectrum antimicrobial efficacy with bis(6-methylheptyl)-benzene-1,2-dicarboxylate and ethyl-pentadecanoate as the main bioactive constituents. Textile samples developed with the extract finishing exhibited excellent antimicrobial efficacy with a growth reduction of 99.9% on Hoheinstein Challenge Test. The wash durability of the finished textile was found good even after 30 washes with commercial detergent.

Sustainable and Economical Production of Biocellulose from Agricultural Wastes in Reducing Global Warming and Preservation of the Forestry

Preservation of the forestry, particularly trees, is essential in managing global warming. However, excessive use of trees for cellulose-based products has continuously depleted world’s forest resources. Nowadays, around 14 % of deforestation is caused by logging for the production of wood cellulose-based products. Many scientists predicted that in 2030, only 10 % of the mature tropical forest will remain. In the era of declining forest resources and expansion of industrialization, it is a worthwhile effort to consider an alternative source of plant cellulose i.e. bacterial cellulose or biocellulose. Biocellulose produced by bacterial fermentation method using various substrates has been proven to be a remarkably versatile biomaterial for a variety of cellulose-based products. Interestingly, the highest cellulose worldwide demands are in the pharmaceutical sector with an annual demand of 30,000 tons. For Malaysia, as a country with vast agricultural areas, the use of generated agricultural wastes such as palm oil mill effluent, pineapple and sugarcane as a fermentation medium can not only avoid environmental pollution but also reduce the production cost. In fact, the use of agricultural wastes as a fermentation medium has proven to reduce 20 % of carbon sources supply for fermentation. In this respect, biocellulose production can play an important role in reducing global warming and preservation of nature.