Showing papers by "Sathyanarayana N. Gummadi published in 2016"

Enhanced production of pectinase by Saccharomyces cerevisiae isolate using fruit and agro-industrial wastes: Its application in fruit and fiber processing

Abstract: The present study is focused on the utilization of fruit and agro-industrial wastes for the production of yeast pectinases using response surface optimization techniques. Orange peel (OP), groundnut oil cake (GC), MnSO4 and incubation period (IP) were found as significant parameters for pectinase production. The central composite design of media optimization indicated that OP (5), GC (4), MnSO4 (0.08%, w/v) and IP (48 h) increased the pectinase production by 9-fold. Crude pectinase promoted the enzymatic peeling of oranges and processing of raw banana fibers. Topographical changes of enzyme treated orange and mango peels were studied using AFM which provides a new tool to unravel the role of pectin aggregation in the dissolution of middle lamella during enzymatic hydrolysis. Changes in the fingerprint regions of enzyme treated fruit substrates were observed along with the disappearance of the impurities such as waxes and pectin using FTIR spectral analysis.

Multi response optimization for enhanced xylitol production by Debaryomyces nepalensis in bioreactor

Abstract: In this study, the optimization of different process variables—pH (4–6), aeration rate (200–550 rpm) and agitation rate (0.6–1.8 vvm) were investigated using rotating simplex method and uniform design method to enhance xylitol production from xylose by D. nepalensis in a batch stirred tank bioreactor. Maximum xylitol productivity (0.576 g L−1 h−1) was obtained at pH 4.0, agitation 300 rpm and aeration 1.5 vvm by rotating simplex method. Individual optimum values of pH, agitation and aeration are 4.2, 370 rpm and 1.2 vvm, respectively, for productivity, 4.3, 350 rpm and 1.0 vvm, respectively for xylitol concentration and 4.4, 360 rpm and 0.8 vvm, respectively for yield. Using generalized distance approach, the simultaneous optimal values were found to be—pH 4.3, 370 rpm and 0.9 vvm. After multi-response analysis, batch fermentation at optimal operating conditions resulted in enhanced productivity (0.76 g L−1 h−1), xylitol concentration (59.4 g L−1) and yield (0.58 g g−1) with an increase of 76.74 % of xylitol productivity.

Characterization and biological activities of cyclic (1 → 3, 1 → 6)-β-glucans from Bradyrhizobium japonicum

Abstract: To isolate cyclic (1 → 3, 1 → 6)-β-glucan from Bradyrhizobium japonicum MTCC120, to characterize its structure and to study its biological activities. The degree of polymerization of cyclic (1 → 3, 1 → 6)-β-glucan varied between 10 and 13 and with substituents acetyl, succinyl and phosphocholine. The cyclic glucans showed bimodal particle size distribution, with hydrodynamic diameters of 1.92 and 231 nm corresponding to monomeric and aggregated cyclic glucans, respectively. SEM and TEM images showed that the glucans formed aggregates of nanorods. The glucans were biocompatible, exhibited good antioxidant activity and had the abilities to bind to Aniline Blue dye to form a fluorescence complex which was concentration dependent. The glucans isolated are cyclic and have good antioxidant activities, hence have potential application in food and pharmaceutical industries. Their dye binding ability could be exploited in medical imaging to reduce the cytotoxicity of the dyes.

Identification and characterization of the novel nuclease activity of human phospholipid scramblase 1

Abstract: Background Human phospholipid scramblase 1 (hPLSCR1) was initially identified as a Ca2+ dependent phospholipid translocator involved in disrupting membrane asymmetry. Recent reports revealed that hPLSCR1 acts as a multifunctional signaling molecule rather than functioning as scramblase. hPLSCR1 is overexpressed in a variety of tumor cells and is known to interact with a number of protein molecules implying diverse functions.

Evaluation of Bio-surfactant on Microbial EOR Using Sand Packed Column

Abstract: Microbial enhanced oil recovery (MEOR) is a technology, which makes use of microorganisms to recover trapped oil from petroleum reservoir. Even after employing primary and secondary recovery techniques in oil fields, approximately two third of original oil in place still remains in the petroleum reservoir and this may be due to higher viscosity of oil which limits its flow. Interfacial tension between water and oil results in higher capillary force which dominates and retains oil in the cap rock. Our main target is to recover the trapped oil using MEOR. In this study, we used Bacillus subtilis MTCC 2422 to produce bio-surfactant using sucrose as carbon source. A sand packed column, which resembles porous petroleum reservoir, was used as model for our study. Vertical column packed with fine sand material was used for this experiment with ambient condition. The column was flooded with water followed by bio-surfactant. To compare oil recovery, Triton X 100, a chemical surfactant was also injected and recovery was observed. Secondary treatment (water injection) gave 27 % oil recovery using sand column experiment and an additional improvement of 9 % was achieved by injecting bio-surfactant yielding a total recovery of 36 %. These results are in comparison with oil recovery using chemical surfactant (34 %). Since bio-surfactants are cheap and biodegradable, they can be safely replaced with chemical surfactants.

Industrial Applications of Caffeine Degradation by Pseudomonas sp.

Abstract: Caffeine is a purine alkaloid naturally present in over 50 plant species with coffee beans, tea leaves and cocoa beans as its main sources. Caffeine majorly enters human system through tea and coffee which are used as the customary drinks throughout the world. High intake of caffeine causes a number of physiological effects on human body. Caffeine also has environmental consequences as effluents released from coffee and tea processing industries are rich in caffeine and pollute nearby water bodies and landmasses affecting natural eco-system. Therefore, decaffeination becomes important from health and environment perspective. Conventional methods of decaffeination include solvent extraction procedures which are toxic, expensive and non-specific. Microbial caffeine degradation can overcome these disadvantages as they are safe and eco-friendly. In this study, induced cells of Pseudomonas sp. were used to degrade caffeine in the effluent collected from Theni unit of Tata Coffee’s Instant Coffee Division and in commercially available tea samples from AVT. Caffeine (0.1 g/l) in the effluent was degraded completely within half an hour when pH of the effluent was adjusted to 7.8 and 8 g/l of induced Pseudomonas cells were used. Among various matrices used for immobilizing Pseudomonas sp., calcium alginate was found to be the best degrading 93 % of caffeine in 3 h when 18 % inoculum was used. Several studies were also done to show that caffeine in tea samples can be effectively removed without significant reduction in polyphenol content by sequential addition of induced Pseudomonas sp. This study has shown that Pseudomonas sp. is an efficient candidate for development of biological decaffeination techniques.