Deepika Dave

Marine Oils as Potential Feedstock for Biodiesel Production: Physicochemical Characterization

Physico-chemical characteristics of four crude marine oils including farmed salmon, seal, cod liver and wild salmon are compared and interpreted with regard to their suitability as biodiesel feedstock. The physico-chemical properties including specific gravity, pH, ash content, acid value, iodine value, saponification value, p-anisidine value, peroxide value, TOTOX value, free fatty acid, flash point, kinematic viscosity, refractive index, lipid classes and fatty acid classification of all four marine oils were evaluated. The characterized marine oils were pale yellow to orange in color and stable in the liquid state at room temperature. The pH (6.5-6.8) values of all oils were neutral. The specific gravity (0.921-0.924 g/cm3), water content (179-325 ppm), ash content (0.0027-0.00455%), free fatty acids (0.03-1.23%), acid value (0.057-0.771 mg KOH/g), peroxide value (5.13-9.17 meq O2/kg oil) and p-anisidine value (3.36-9.67) of all oils were within recommended limits except for higher water content in the seal oil (689 ppm), higher acid value in farmed salmon (2.441 mg KOH/g) and seal oil (0.958 mg KOH/g) and higher iodine value (116-139.15 g I2/100 g). A drying step needs to be implemented for the removal of water as it can lead to corrosion of internal combustion engine components. Due to higher iodine values, all the oils were drying oils except farmed salmon oil which was semidrying oil and susceptible to become rancid which causes reduction of pour point of biodiesel produced in the absence of antioxidant. All four marine oils were more likely to polymerize in the heat of the engine if used directly without trans-esterification. Flash point of all marine oils were above 200°C so, there is no risk of fire outbreaks in case of accidents. Due to higher triacylglycerol (81-93%) content, all the marine oils are suitable as a feedstock for biodiesel production via trans-esterification. Cod liver (14.72%) and wild salmon oil (9.92%) were rich in polar lipids while the farmed salmon (2.43%) and wild salmon (2.43%) were low in polar lipids. The phospholipids (1.21-1.67%) were higher than the recommended limit of ≤10 ppm so degumming process is required prior to biodiesel production. All the marine oils in this study have a high degree of unsaturation and polyunsaturated fatty acids and therefore the biodiesel produced from all oils will have less oxidation stability and result in the precipitation of the biodiesel components in a fuel feeding system or combustion chamber. Therefore, it is essential to stabilize the oil using an antioxidant immediately after extraction/production to obtain a high quality biofuel.

Extraction of Chymotrypsin from Red Perch (Sebastes marinus) Intestine Using Reverse Micelles: Optimization of the Backward Extraction Step

Fish processing waste can be used to produce valuable by-products such as chymotrypsin which has applications in the food, leather, chemical and clinical industries. In this study, a reverse micelles system of AOT/isooctane was used to extract chymotrypsin from crude aqueous extract of red perch intestine. The effects of pH and KCl concentration of the backward extraction step on the total volume (TV), volume ratio (VR), total activity (TA), enzyme activity (AE), specific activity (SA), purification fold (PF), protein concentration (Cp) and recovery yield (RY) were studied. Changing the pH from 6.5 to 8.5 and the KCl concentration from 0.5 to 2.0 M during the backward extraction step had no effects on the TV or VR. Increasing the pH from 6.5 to 7.5 increased AE, SA, Cp, PF and RY by up to 47.06%, 30.0%, 27.0%, 26.9% and 18.47%, respectively but they all then declined with further increases in the pH. Similar trends were observed when the KCl concentration was increased from 0.5 to 1.5 M. The decreases in these parameters were due to the denaturation of protein under high pH. The highest AE, Cp and RY were achieved with pH 7.5 and 1.0 M KCl concentration while the highest SA and PF were achieved with pH 7.5 and 1.5 M KCl concentration. Addition of isobutyl alcohol in the backward extraction step increased the TV, AE, TA, Cp, SA, PF and RY by 13.6%, 336.4%, 342.6%, 81.1%, 146.4%, 146.2% and 345.8%, respectively. Alcohol reduced the interfacial resistance for the reverse micelles and, thus, destroyed the reverse micelles structure. The values of AE, TA, SA, PF and RY obtained with reverse micelles methods were much higher (2.3 fold) than those obtained with the ammonium sulphate method.

Changes in Cell Structure, Morphology and Activity of Streptomycesvenezuelae during the Growth, Shocking and Jadomycin ProductionStages

Streptomyces venezuelae have the ability to synthesize a group of novel benzoxazolophenanthridine antibiotics called jadomycin. The aim of the study was to investigate the changes in activity, cell structure and morphology of Streptomyces venezuelae while subjected to different environmental conditions during the growth, ethanol shocking, and jadomycin production stages. The activity of S. venezuelae was measured using the triphenyl tetrazolium chloride (TTC) technique while the microbial population was measured using the optical density and plate count techniques. Samples from each stage were viewed under the scanning electron microscope (SEM) and transmission electron microscope (TEM). The specific TF yield was calculated by dividing the TF yield by the number of cells. The specific TF yield remained constant at 2.44 x 10-8(μmol/CFU) during the growth period in nutrient rich medium and decreased to 0.25 x 10-8 μmol/CFU and 0.28 x 10-8 μmol/CFU during the acclimatization to the nutrient deprived-amino acid rich production medium and after shocking and then increased to 3.67 x 10-8 μmol/CFU during jadomycin production. The ethanol shock did not cause 100% of the cells to change their morphology. Remarkable changes were observed in the morphology and structure (cell diameter, vacuoles present and septation/sporulation) of S. venezuelae during the four consecutive stages (growth, acclimatization, shocking and jadomycin production). The elemental analysis provided information for verifying jadomycin B purity (97.86%). However, it was not possible to detect jadomycin B within cells. It is probable that jadomycin was produced outside the cells by extracellular enzymes as opposed to intracellularly by the uptake of isoleucine and glucose. The white pellets (cells), obtained by centrifugation of production medium, supports the idea that jadomycin B is produced outside the cells as jadomycin is highly coloured compound. It is also possible that the cells were highly efficient at excreting the secondary metabolites. These hypotheses need further investigation.

Partition of Pepsinogen from the Stomach of Red Perch (Sebastes marinus) by Aqueous Two Phase Systems: Effects of the Salt Type and Concentration

An important acidic protease, pepsin is synthesized and secreted in the gastric membrane in an inactive state called pepsinogen (PG) and has applications in the food and manufacturing industries, collagen extraction, gelatin extraction and in regulating digestibility. Fish processing waste can be used to produce commercially valuable byproducts such as pepsinogen. In the present study, the purification of pepsinogen from the stomach of red perch using aqueous two phase systems (ATPS) formed by polyethylene glycol (PEG) and salt at 4°C was optimized. The effects of salt type (MgSO4, (NH4)2SO4, Na3C6H5O7 and K2HPO4) and concentration (6, 7, 8, 9, 10, 11, 12, 13, 15, 17, 19%) on the partitioning of PG were studied and parameters including total volume (TV), volume ratio (VR), enzyme activity (AE), protein content (Cp), specific activity (SA), partition coefficient (Kp), purification fold (PF) and recovery yield (RY) were evaluated. Salt type and salt concentration had significant effects on each parameter. MgSO4, (NH4)2SO4, Na3C6H5O7 and K2HPO4 required different critical salt concentrations (9, 12, 12 and 10%, respectively) to form biphasic systems. TV and VR decreased with increased salt concentration since salt formed hydrogen bonds with water molecules and created a more compact and ordered water structure. AE, CP, SA, PF and RY showed a maximum increase with intermediate salt concentration, while KP had the opposite pattern. The highest TV and AE values were obtained at 12% (NH4)2SO4 while the highest SA and PF values were obtained at 12% MgSO4. The highest TV and Cp values were obtained at 12 and 15% Na3C6H5O7, respectively. (NH4)2SO4 at 15% concentration gave the highest RY (71.7%) and was selected as the optimum salt type and concentration. Thus, 15% (NH4)2SO4 18% PEG 1500 was the optimal ATPS combination and presented the best partition. The values of SA and PF and RY obtained with ATPS method were two fold higher than those obtained with the ammonium sulphate fractionation (ASF) method.

Study of drying kinetics of salmon processing by-products at different temperatures and the quality of extracted fish oil

ABSTRACT Samples of salmon processing by-products were minced, mixed, and partially dried to moisture content of 90 ± 5% (dry basis), at two different temperatures 60 and 100°C (using hot air-drying and oven-drying, respectively). Theoretical and semitheoretical drying models were used for modeling of the drying kinetics of salmon by-products mix, where Page model and logarithmic models were observed as the best models presenting the drying kinetics of salmon by-products at 60 and 100°C, respectively. Salmon by-product oil was extracted from the partially dried by-product through centrifugation and was compared with enzymatically extracted (enzymatic extraction method was considered as the control method) salmon oil, in terms of fatty acid profile of the oils. The oil content obtained through semidried samples and enzymatically treated samples ranged between 16.234 and 18.212 g/100 g of fresh sample, which were not significantly different. The fatty acid composition was similar in all the cases. The fatty acids predominantly observed in the salmon oils included oleic acid, linoleic acid, and palmitic acid. Other fatty acids included palmitoleic acid, stearic acid, vaccenic acid, gondoic acid, and myristic acid. Docosahexaenoic acid and eicosapentaenoic acid contents were between 1 and 2% of the oil extracted in all the cases, and DPA (Docosapentaenoic acid) content was approximately 1%. Hence, partial dehydration at both the temperatures was concluded as a potential processing method for increasing the storability of salmon by-products and obtaining salmon oil with high quality.

Augmenting Composting Microbial Community with Thermophilic Cellulolytic Organisms for Enhanced Degradation of Phenolic Compounds in Creosote Treated Wood Waste

Creosote is widely used as a wood preservative in railway sleepers, utility poles, bridges, building foundations, fences, stakes for vegetables and fruits, garden furniture and outdoor recreational facilities. Contamination of soil and water and threat to human and animals health are the major constraints to disposal of creosote-treated wood waste. Composting provides a treatment option for creosote-treated wood waste and production of a value- added product. The aim of this study was to test the effectiveness of inoculating the composting process with three thermophilic-cellulolytic microorganisms ( T. curvata , T. aurantiacus and T. fusca ) in degrading phenols in creosote treated wood waste. Used cooking oil was added into the composting system as a bio-available carbon source. The temperature, pH, moisture content, solids, total carbon, nitrogen, phenols, cellulose and lignin were monitored. The temperature profiles showed that the thermophilic phase (>45 ?C) was achieved and successfully maintained due to the addition of used cooking oil. The moisture content decreased because the water produced by microbial respiration did not compensate for the water vapour lost with the exhaust gases. The breakdown of organic nitrogen to ammonium caused an initial increase in the pH which was then decreased due to the formation of organic acids from the decomposition of fats and the loss of ammonia with the exhaust gases. The inoculated experiments achieved higher reductions in volatile solids, total carbon, TKN, phenols, cellulose and lignin compared to the control. Different degradation rates were observed in the psychrophilic, mesophilic and thermophilic stages of composting. The product from the inoculated experiment had improved stability and phytotoxicity compared to that of the control (uninocualted). The inoculation of thermophilic-cellulolytic microorganisms ( T. curvata , T. aurantiacus and T. fusca ) accelerated the composting process and resulted in higher degradation of phenolic compounds, lignocellulose and lignin.

Efficacy of various biosorbents for removal of endosulfan from water environment

In this study, the efficacy of biosorbents prepared from various cultures for removal of endosulfan from water environment was evaluated. Seven different biosorbents from Bacillus subtilis, Bacillus megaterium, Escherichia coli, Rhizopus arrihzus, Aspergillus nidulans, Cladosporium and activated sludge biomass were synthesised and assessed for biosorption of endosulfan from water environment. Biosorption experiments were conducted for each biosorbent with 1 mg/l endosulfan solution at 250 rpm for three days at biosorbent doses ranging 2.5–50 mg. Saturation capacity of the biosorbent was taken as the key parameter for selecting the most suitable biosorbent for further research. The isotherms were developed for all biosorbents and linear regression analysis was carried out with BET, Freundlich and Langmuir adsorption equilibrium models to determine the saturation capacities. The biosorbent prepared from fungal strain Aspergillus nidulans was found to be most appropriate as it exhibited the maximum saturation capacity of 43.6 mg/g of endosulfan among all biosorbents.

Partition of Pepsinogen from the Stomach of Red Perch (Sebastes marinus) by Aqueous Two Phase Systems: Effects of PEG Molecular Weight and Concentration

Fish processing waste can be used to produce commercially valuable by-products, such as pepsinogen, which has application in food, manufacturing industries, collagen extraction, gelatin extraction, and in regulating digestibility.An important acidic protease, pepsin, is synthesized and secreted in the gastric membrane in an inactive state called pepsinogen (PG). In the present study, the purification of pepsinogen from the stomach of red perch, using aqueous two phase systems (ATPS) formed by polyethylene glycol (PEG) and salt at 4°C, was optimized.The effects of PEG molecular weight (PEG 1000, 1500, 3000 and 4000) and concentration (16, 18, 20, 22 and 24%) on the partitioning of PG were studied, and parameters including total volume (TV), volume ratio (VR), total enzyme activity (AE), protein content (Cp), specific enzyme activity (SA), partition coefficient (Kp), purification fold (PF), and recovery yield (RY) were evaluated. PEG molecular weight and PEG concentration also had significant effects on each parameter. TV and VR decreased with increased salt concentration, since salt formed hydrogen bonds with water molecules and formed a more compact and ordered water structure. PG partitioned predominantly in the PEG-rich top phase due to its negative charge. AE, CP, SA, PF and RY increased with increased salt concentration and then decreased, while KP had an opposite pattern. The PEG 3000 (20%), PEG 1000 (24%), PEG 4000 (16%) and PEG 1000 (18%) concentrations gave the highest TV, VR, CP and KP, respectively. PEG 1500 with 18% concentration gave the highest AE, SA, PF and RY (86.2%). As PEG 1500 at 18% concentration gave the highest RY (86.2%). It was selected as the optimum PEG molecular weight and PEG concentration. (NH4)2SO4 at 15%, which gave the highest RY (71.7%), was selected as the optimum salt type and salt concentration. 15% (NH4)2SO418% PEG 1500 was the optimal ATPS combination, and presented a better partition. The values of SA and PF and RY obtained with ATPS method were much higher (2 fold in case of SA and PF, and 1.2 fold in case of RY), than those obtained with the Ammonium Sulphate Fractionation (ASF) method.