Roslinda Malek

Scaling up, characterization of levan and its inhibitory role in carcinogenesis initiation stage'.

Honey isolate Bacillus subtilis M was cultivated in shake flasks and in 16-l bioreactor cultures to investigate cell growth, bio-metabolites production kinetics and bioprocess scalability. The respective maximal levan and levansucrase productions of 59.5 g/l and 74.1 U/ml were achieved in bioreactor cultures under pH controlled condition (pH=7.0) after only 24 h. Crude levan (levE) was isolated, characterized and fractionated into F1, F2, and F3 with different molecular weight (21.8, 13.118, 9.53 kDa). (1)H NMR and (13)C NMR spectroscopy proved that LevE and their fractions were mainly β-(2, 6)-linked levan-type polysaccharide. The cancer chemo-preventive activity indicated that the levE and its fraction 3 were promising inhibitors of cytochrome P-450 1A activity, inducers of glutathione-S-transferase activity in Murine hepatomaHepa1c1c7cells and possessed highest radical scavenging affinity to both ROO and OH. They inhibited the induced-DNA fragmentation. None of the tested samples triggered apoptosis or necrosis in splenocytes, except F2.

Optimization of ingredient and processing levels for the production of coconut yogurt using response surface methodology

In this study, response surface methodology (RSM) was employed to optimize the ingredient formulation and processing parameters of coconut milk yogurt production such as temperature, time, and amount of starter culture on the sensory evaluation responses. Besides, the physicochemical properties such as pH, titratable acidity, and viscosity of the yogurt were also analysed. The analyses show that the coconut yogurts have a pH from 4.01 to 5.79, acidity from 0.461 to 2.079 (%), and viscosity from 433 to 21,833 cp during the optimization process. From the analysis of variance, the R2 of all response variables is more than 0.73 that indicates that a high proportion of variability was explained by the model. Based on the response surface 3D plot of the sensory evaluation, the optimum acceptability of the coconut yogurt processing parameter are at temperature of 37oC, 8 h of the fermentation duration, and 3%(w/w) of the starter culture.

Efficient production process for food grade acetic acid by acetobacter aceti in shake flask and in bioreactor cultures

Acetic acid is one of the important weak acids which had long history in chemical industries. This weak organic acid has been widely used as one of the key intermediate for many chemical, detergent, wood and food industries. The production of this acid is mainly carried out using submerged fermentation system and the standard strain Acetobacter aceti. In the present work, six different media were chosen from the literatures and tested for acetic acid production. The highest acetic acid production was produced in medium composed of glucose, yeast extract and peptone. The composition of this medium was optimized by changing the concentration of medium components. The optimized medium was composed of (g/L): glucose, 100; yeast extract, 12 and peptone 5 and yielded 53 g/L acetic acid in shake flask after 144 h fermentation. Further optimization in the production process was achieved by transferring the process to semi-industrial scale 16-L stirred tank bioreactor and cultivation under controlled pH condition. Under fully aerobic conditions, the production of acetic acid reached maximal concentration of about 76 g/L and 51 g/L for uncontrolled and controlled pH cultures, respectively.

Bioprocess development for kefiran production by Lactobacillus kefiranofaciens in semi industrial scale bioreactor

Lactobacillus kefiranofaciens is non-pathogenic gram positive bacteria isolated from kefir grains and able to produce extracellular exopolysaccharides named kefiran. This polysaccharide contains approximately equal amounts of glucose and galactose. Kefiran has wide applications in pharmaceutical industries. Therefore, an approach has been extensively studied to increase kefiran production for pharmaceutical application in industrial scale. The present work aims to maximize kefiran production through the optimization of medium composition and production in semi industrial scale bioreactor. The composition of the optimal medium for kefiran production contained sucrose, yeast extract and K2HPO4 at 20.0, 6.0, 0.25 g L−1, respectively. The optimized medium significantly increased both cell growth and kefiran production by about 170.56% and 58.02%, respectively, in comparison with the unoptimized medium. Furthermore, the kinetics of cell growth and kefiran production in batch culture of L. kefiranofaciens was investigated under un-controlled pH conditions in 16-L scale bioreactor. The maximal cell mass in bioreactor culture reached 2.76 g L−1 concomitant with kefiran production of 1.91 g L−1.

Improvement of cell mass production of Lactobacillus delbrueckii sp bulgaricus WICC-B-02: A newly isolated probiotic strain from mother’s milk -

Lactobacillus delbrueckii sp bulgaricus WICC-B-02 is new probiotic strain which was initially isolated from the mother’s milk. As lactic acid bacterium, it’s known as a highly efficient probiotic microorganism with a wide range of benefits on the human health. This study was conducted to design and establish industrial platform for high cell mass production of L. delbrueckii sp bulgaricus for pharmaceutical and food industries application. However, due to low cell mass production caused by the accumulation of lactic acid during the cultivation of lactic acid bacteria, therefore, the optimization of cell mass production with low lactic acid production was developed in this study. The new formulation of the production medium was developed by optimizing the main components such as glucose (30 g.L-1), yeast extract (6.0 g.L-1) and peptone (6.0 g.L-1) in shake flask cultivation. The cell mass production was 3.14 g.L-1, and it increased to 6.08 g.L-1 with the lactic acid production being reduced by about 33%, compared to the un-optimized medium.

Microbial Xylanases: Sources, Types, and Their Applications

Biomass conversion to an utilizable energy sources such as monomer sugars using enzymatic hydrolysis has been emerged as the current technology which promises the future energy. In nature, bioconversion process of biomass is mediated by a group of biofunctional hydrolytic enzymes. These enzymes generally work in cooperative synergetic action to facilitate enhanced effective degradation of biomass. Xylanase is one of the crucial hydrolytic enzymes involved in hydrolysis of xylan, the hemicellulose which constitutes 15–30 % of the plant biomass. This chapter discusses in detail about the enzymatic hydrolysis of xylan by the xylolytic enzyme endo-1,4-β-xylanase, its occurrence in nature and mode of action, structure and classifications, current methods for its production, purification, and characterization. In addition, the major and recent industrial applications of this enzyme were highlighted as well.

A review on fruit juice probiotication: Pomegranate

Foods and beverages containing live microbes (probiotics) are increasingly promoted by health professionals nowadays. The probiotic products in the market are mostly milk-based products, for instance yoghurts. There has been a high demand for the non-dairy probiotic products from those having the lactose intolerance problem and/or worry about the high cholesterol content. Therefore, fruit is now becoming the preferable matrix for probiotic delivery in human body. Fruits could be another promising carrier for probiotic strains, particularly from the genera of Lactobacilli and Bifidobacteria. Somehow, the cell viability and stability are highly fruit and strain dependent, in addition to the processing factors and storage temperature. In the present review, fruits, particularly pomegranate is critically highlighted as a potential fruity vehicle for probiotic microbiota. Pomegranate contains bioactive secondary metabolites (anthocyanins, ellagic acid derivatives and hydrolyzable tannins) and non-digestible carbohydrates (prebiotics). The low pH value of pomegranate juice could be compromised by mixing with other fruits or by protecting probiotics from acidic environment by microencapsulation. This review covers the previous works which were carried out on the fruit-based probiotic foods and beverages, supported by the mechanistic explanation on the action of probiotics in human body.