Amino acids are the basic bioelements of proteins. And proteins are the very essential macromolecules for the functions of humans and animals. Lysine, or L-Lysine, is one such important amino acid for proper growth in human beings. It also plays an important role in the production of carnitine, a nutrient responsible for converting fatty acids into energy. It also plays an important role in calcium absorption by the body as also in the formation of collagen that in turn is essential for bone formation. But being an essential amino acid, it is not produced by the body. Therefore, it has to be supplied through food. Thus the demand for Lysine has been steadily increasing over the years.

L-Lysine can be produced either chemically or biochemically. The stereo-specificity of amino acids, however, makes their production through fermentation mechanism advantageous compared to synthetic processes. With the increased competition in amino acid industry, biotechnology companies have been continuously coming up with innovative research developments and complex management concepts to produce amino acids cheaply using strains of the gram positive corynebacteria so as to gain market leadership.

Much research has been carried out on the improvement of L-Lysine producing bacterial strains, for the conversion under fermentation process is dependant on the characteristics of the bacterial strains. Nevertheless, productivity is also effected by the growth rate of a strain, rate of sugar utilization/the culture conditions. Against this backdrop, the authors, B Sarva Rao, Ch V R Murthy and A V N Swamy of the first paper of the issue, “Studies on Continuous Reactor Kinetics of L-Lysine by Immobilized Corynebacterium glutamicum Cells”, investigated the dependence of dilution rate on substrate utilization rate and cell productivity in continuous culture studies. Their study revealed that concentration of L-Lysine was improved to a maximum level of 45.34 g/L, while the yield was 0.55 g/g at an optimum dilution rate of 0.3 1/h and operating conditions of fermentation time

72 h, pH 7.5, temperature 35 °C and glucose concentration of 90 g/L per. Moving on to butanedioic acid which is an important ingredient in the manufacture of various specialty and commodity chemicals, L N Mauro Oliveira, Vanusa M F Oliveira, Leticia R Oliveira and Moilton R Franco Junior, the authors of the next paper, ”Solubility of Butanedioic Acid in Solutions of Water-Ethanol and Water-Propanol From 293.2 K to 333.2 K”, determined the solubilities of butanedioic acid in some pure solvents and in binary mixtures of water-ethanol and water-1-propanol using a gravimetrical method at temperatures between 293.2 K and 333.2 K. Their findings showed a maximum acid solubility value in all systems tested. The calculated solubility is found to be in agreement with experimental values, which means the correlated polynomial equation used by the authors could provide essential data for manufacturing and purifying processes in the industry.

Now moving to industrial activities and the resulting pollution, M Sujatha, P Kalpana, D A Naidu, P King and V S R K Prasad, the authors of the next paper, ”Kinetic Modeling of Biosorption of Cadmium by Syzygium cumini (L.) from Aqueous Solution”, conducted a study using Syzygium cumini as biosorbent to remove the industrial pollutant, cadmium from aqueous solution. Their findings revealed that S. cumini is an effective biosorbent for absorbing cadmium ions from aqueous solution, for it has higher content of hydroxyl and amine groups. Biosorption is found to be rapid and equilibrium was obtained at 20 min for Cd(II) ion and kinetics fitted second-order model well.

Moving on to the important material in manufacturing industry, aluminum, Vijay Singh Sikarwar, Sandeepan Ray, Vijay Agrawal and Parmesh Kumar Chaudhari, the authors of the next paper, “Effect of Various Parameters on Cell Temperature for Production of Aluminum”, keeping in mind the fact that the economic efficiency of an electrolyte cell meant for production of aluminum from alumina depends on the temperature inside the cell, analyzed the performance of a set of 30 electrolytic cells under varying parameters like bath height, metal height, excess AlF3 and Al2O3 that effect the cell temperatures. The authors concluded that bath temperature should be maintained as close as possible to standard operating temperature to achieve maximum efficiency in aluminum production. They also infer that bath temperature can be controlled by controlling process variations like energy input into the cell, percentage of AlF3 and Al2O3, bath height, and metal height in bath. The authors are of the opinion that the best operating cell always run at 11-12% AlF3, which maintained the temperature between 940-970 °C, the most favorable temperature for production of aluminum.

In the next paper, ”CFD Simulation of Heat Transfer Characteristics in Pilot Plant Scale Bubble Column”, its authors Lutukurthi D N V V Konda and P Sivashanmugam, reported the heat transfer characteristics of a semi batch gas (air) –liquid (water) up-flow bubble column by CFD and comparing the simulated results obtained with the experimental results found in the literature, concluded that the simulated radial heat transfer profiles are in agreement with those in the literature.

In the next paper of the issue, ”Assessing the Behavioral Aspects of Gas-Solid Fluidization”, authors, V K Singh, Surjit Parial, Ankit Kumar Singh, Amit Keshav and H Kumar, presented the importance of fluctuation ratio in the context of uniform gas-solid fluidization: One, fluctuation ratio for the same air mass velocity decreases with an increase in the bed height, while all other distributor parameters remain unchanged; two, an increase in the particle size leads to better fluidization quality; and three, an increase in the free flow area for air through the distributor results in more non-uniformity in fluidization.

The authors, Bhupen Kumar Baruah, Chitrani Medhi and Abani Kumar Misra, in their paper, “Water Filtration Technique in Rural Areas of Assam: A Study on Iron Removal by Bamboo Charcoals”, carried out a study to remove iron using four different bamboo charcoals separately in the common water filtration technique that is in vogue in Assam and found that though all the four types of charcoals were effective in removing iron from water, it is the charcoal from Bambusa balcooa which is more effective in bringing down iron levels in water to desirable limits.

-- GRK Murty
Consulting Editor