Kinetic studies on recombinant stem bromelain

Stem bromelain is a plant thiol protease with several industrial and therapeutic applications. This current work presents kinetic studies of recombinant bromelain (recBM) expressed in Escherichia coli BL21-AI on foursynthetic substrates, N-α-carbobenzoxy-L-alanyl-p-nitrophenylester (ZANPE), N-α-carbobenzoxy-L-arginyl-L-ar-ginine-p-nitroanilide (ZAANA), N-α-carbobenzo-xy-L-phenylalanyl-L-valyl-L-arginine-p-nitroanili-de (ZPVANA) and L-pyroglutamyl-L-phenylalanyl-L-leucine-p-nitroanilide (PFLNA). Hydrolytic activities of recBM at various pH and temperature conditions were compared to that of commercial bromelain (cBM). Both enzymes demonstrated high activities at 45o C and pH 5 - 8 for recBM and pH 6 - 8 for cBM. recBM showed marginally lower Kmand slightly higher kcat/Kmfor ZAANA, ZANPE and ZPVANA in comparison to cBM.trans Epoxysuccinyl-L-leucylamido {4- guanidino}butane (E-64) severely affected recBM and cBM hydrolysis of the synthetic substrates by competitive inhibition with Kivalues of 3.6 - 5.1 μM and 5.5 - 6.9 μM for recBM and cBM, respectively. The evaluated properties of recBM including temperature and pH optima, substrate specificity and sensitivity to inhibitors or activators, satisfy the requisites required for food industries.

A review of chemical absorption of carbon dioxide for biogas upgrading

Significant attention has been given to biogas production, purification and upgrading as a renewable and clean fuel supplement. Biogas is a product of an anaerobic digestion process comprising methane, carbon dioxide,and trace amounts of other gases. Biogas purification removes trace gases in biogas for safe utilisation. Biogas upgrading produces methane-rich biogas by removing bulk carbon dioxide from the gas mixture. Several carbon dioxide removal techniques can be applied for biogas upgrading. However, chemical absorption of carbon dioxide for biogas upgrading is of special significance due to its operation at ambient or near ambient temperature and pressure, thus reducing energy consumption. This paper reviews the chemical absorption of carbon dioxide using amine scrubbing, caustic solvent scrubbing, and amino acid salt solution scrubbing. Each of these techniques for biogas upgrading is discussed. The paper concludes that an optimised implementation of the chemical absorption techniques for biogas upgrading requires further research.

The Growth Study of Vero Cells in Different Type of Microcarrier

The fact of microcarrier (MC) culture introduces new possibilities and makes possible the practical high-yield culture of anchorage-dependent cells has generated a considerable focus in this study. The objective of this research was to study the comparison of Vero cell growth on different types of commercial microcarriers;Cytodex-1, Cytodex-3, Hil-lex? II and Plastic Plus in spinner vessel and two liters bioreactor cultured for 96 hours. Biological performance of the microcarrier in RPMI media showed the preference of Vero cell grew on Cytodex 3 microcarriers with highest maximum viable cell number (2.4 × 105 cells/ml) followed by Cytodex 1, Hillex and Plustic Plus. Vero cell on Cyto-dex-3 data in spinner flask was compared in bioreactor and result showed higher viable cell number in biorector. Thus, this dextran-crosslink gelatin microcarrier (Cytodex 3) provided the best surface for cell attachment and fast proliferation. At the end of this cell growth improvement will be used for virus transfection producing a vaccine in bioreactor.