Current Biotechnology - Volume 1, Issue 3, 2012

Aspartase (L-aspartate ammonia-lyase; EC 4.3.1.1) catalyzes the reversible amination of fumaric acid to produce L-aspartic acid. Aspartase producing bacterial strains were isolated from the effluent of a fertilizer industry. The effluent was alkaline in nature and rich in nitrogenous contents. Aspartase producing bacterial strains were isolated by enrichment technique. Screening of isolated strains for aspartase activity has shown isolate NFB-5 to be the most efficient aspartase producer. This isolate showed higher aspartase activity than reference strains of Escherichia coli and Bacillus cereus. The genus of strain was identified by morphology, physiological and biochemical tests. Species specific identification was determined by 16S rDNA analysis. The phylogenetic analysis identified the isolate as Aeromonas media NFB-5, a motile member of aeromonads of family Aeromonadaceae which are ubiquitous inhabitants of fresh water and estuarine environments. The strain was capable of expressing maximum aspartase (48.22±0.324 U/g fresh biomass) within 24 h of growth at 37ºC. Aspartase gene (aspA) from A. media has been successfully cloned and sequenced. The gene consisted of an ORF of 1,424 bp encoding a protein of 474 amino acid residues. The amino acid sequence of the enzyme showed a high degree of identity (91%) to aspartase from E. coli but differed from aspartases from other microorganisms. The results suggest that A. media NFB-5 is a new potent aspartase producer and cloning of its aspartase gene (aspA) having potential applications in food industry.

Biotransformation of (-)-α-santonin using Aspergillus parasiticus resulted in the production of 3,4-epoxy-α-santonin, 4,5-dihydro-α-santonin and 1,2-dihydro-α-santonin and 3 minor products and the biological activity of the transformed products was established by antibacterial & antifungal assays. 3,4-epoxy-α-santonin exhibited higher degree of antibacterial and antifungal activity. 4,5-dihydro-α-santonin showed slight increase in the activity, compared to (-)-α-Santonin. 1,2-dihydro-α-santonin is equipotent to the substrate ( (-)-α-Santonin ). This is the first report on the Biotransformation of (-)-α-Santonin by Aspergillus parasiticus and evaluation of the biological activities of the biotransformed products.

This paper deals with the complex problem of modeling of water UVc disinfection, and it aimed to improve the performances of this multipart process. The UV disinfection should inactivate pathogenic microorganisms and improve the hygienic quality of water. A comprehensive treatment in considering the mathematical aspect to model the UVc disinfection of water was achieved. A complete mathematical description of the inactivation kinetics is developed and showed two successive stages, a fast and a low one. Similarly, a mathematical model describing fluid flow and concentration of the microorganisms inside a UV reactor is developed. Modeling the kinetic and the UV lamp ray emission using some empirical approaches might increase the efficiency of UV disinfection and improved its performance. This study showed an improvement of the microbial inactivation rate of about of 49% for the selected pathogenic resistant bacteria of Pseudomonas aeruginosa ATCC 15442, and in considering perfectly mixed water flowing into the UV reactor.

The use of Henna wood as a raw material to produce activated carbon by physical activation was investigated. The activated carbons produced were characterized by Nitrogen adsorption isotherms and point of zero charge (pHPZC) properties. BET (Brunauer, Emmett and Teller) surface area of the activated carbon was determined as 584 m2/g. The removal of Basagran from aqueous solutions by adsorption on activated carbon produced has been studied. The adsorption capacity of the activated carbon was found to be of 134.78 mg/g of the adsorbent. Results were analyzed by the Langmuir and Freundlich equations using linear correlation coefficient at different temperatures. Thermodynamic features such as adsorption enthalpy (ΔHad), adsorption entropy (ΔSad) and free enthalpy (ΔGad) were determined.

Hydrogen production involves the use of hydrogenase (H2ase) enzyme, especially for photohydrogen production. Specific detection of fermentative hydrogen producing bacteria from the microbial communities is achieved based on the universal Iron-hydA primers. In the present study, the primers for the H2ase gene were designed, followed by the isolation of the DNA from the selected hydrogen producing microorganisms. Amplification of the genome by the designed primers were carried out by the polymerase chain reaction. The PCR primers designed were HyF, Hyff, HyR and Hyrr. The primers were analyzed and best fitted by the computer aided program. The resulted primers were amplified (400 bps) from the genome of the selected hydrogen producing microorganisms. This work was carried out as a preliminary assay in molecular cloning of hydrogenase genes by primer designing from the selected strains for the improvement of hydrogen production process.

An efficient protocol for plant regeneration from protoplasts in Catharanthus roseus is reported. Hypocotylderived embryogenic callus was used as a source of protoplasts. The embryogenic suspension was established in liquid MS, added with 1.0 mg l-1 NAA and 1.0 mg l-1 BAP; and then suspension was treated with various enzymatic solutions either alone or in combinations. The cocktail of cellulase (2.0%), pectinase (1.0%), macerozyme (0.02%) and driselase (0.50%) showed maximum yield of protoplasts (37.25 ± 1.86a X 105 with highest viability (65.25 ± 3.26a). The yield (8.50 ± 0.42a X 106 and viable protoplasts number (70.18 ± 3.51a) was even more when sorbitol was added with above enzyme mixtures as osmoticum. In 0.50 mg l-1 NAA +0.50 mg l-1 2, 4-D containing medium, protoplasts divided well and maximum number of micro colony formation was noticed (13.33 ± 1.53a/Petriplate). The callus biomass (fresh weight) was, however low in protoplast derived embryogenic callus (PDEC) than in normal embryogenic callus (NEC). Biochemically, the protein, proline, sugar and enzyme activity level (CAT, SOD, GR and APX) were also higher in PDEC than in NEC. The protoplast derived somatic embryos latter germinated and regenerated into plantlets. The recovery period from ‘protoplast to plantlet’ was around 40 weeks in contrast to 16 weeks in normal somatic embryogenesis pathway.

Due to rapid expansion of biodiesel production, the quantity of crude glycerol on the global market has been surging. One marine microalga, Schizochytrium limacinum SR21 has great capability in transforming crude glycerol to intracellular lipids, especially docosahexaenoic acid (DHA). To elucidate the mechanisms involved in glycerol uptake and conversion, the proteomic profiles of cells grown on either glycerol or glucose were obtained using 2-Dimensional fluorescence difference gel electrophoresis (2-D DIGE) and compared. Out of 24 proteins that were made differentially between glycerol and glucose-grown cells at statistically significant levels, 11 proteins strongly related to the metabolism of glycerol were identified. A glycerol conversion pathway was proposed based on key enzymes determined.

The enzymatic esterification of n-propanol with cinnamic acid was carried out with a commercial lipase (Lipolase 100T) immobilized onto silica. The silica pretreated with 1% (v/v) glutaraldehyde showed 95% protein binding efficiency. Esterification reactions were carried out at 45oC under shaking (160 rpm) with 75 mM: 100 mM of cinnamic acid and n-propanol, respectively in DMSO. The maximum yield of n-propyl cinnamate (94 mM) was achieved in 2.5 h at 45oC using 25 mg of silica-bound biocatalyst. Addition of molecular sieves to the reaction mixture had little effect in improving the ester synthesis. In esterification reaction among the tested salt ions, a pre-exposure of the silica-bound lipase to Ca2+ and Cu2+ ions (1 mM) improved the ester yield in DMSO. The silica-immobilized lipase retained ~39% of its original efficiency after 7th repetitive cycle of esterification. The n-propyl cinnamate synthesis when scaled up to 50 ml batch reaction yielded 79 mM of the ester. Thus the study achieved a good yield of n-propyl cinnamate synthesis in DMSO in a scaled-up reaction system under optimized conditions using silica-bound lipase.

Lipase catalysis plays a vital role in the synthesis of a variety of compounds of commercial value in food, pharmaceutical as well as in detergent industry. In the present study a commercial lipase, Lipolase T20 was immobilized onto natural fibers of dried coconut fruit by incubating the fiber's bunch in the enzyme solution for 12 h at 8oC. The fiberbound lipase was thereafter treated with 2% (v/v) glutaraldehyde. The fiber-immobilized biocatalyst was optimally active at pH 8.0 and at a temperature of 55oC. The fiber-bound lipase showed maximum hydrolytic activity towards pnitrophenyl palmitate. Among various non-ionic detergents, the exposure to Tween-60 (a non-ionic detergent) enhanced the activity of fiber-bound lipase towards the hydrolysis of p-nitrophenyl palmitate (p-NPP). Among various selected salt ions (1 mM), Al3+, Zn2+, Ca2+, Cu2+ and Fe2+ ions promoted, while Pb2+, Na+, Mn2+ and NH4 + ions decreased the hydrolytic activity of fiber-bound lipase. The immobilized lipase retained more than 45% of its original activity after 5th repetitive cycle of hydrolysis. The immobilized lipase also successfully achieved the esterification of 2-octanol (75 mM) and ferulic acid (100 mM) in DMSO in 3 h at 55oC under shaking at180 rpm.

Insects, mites, fungi, viruses, and bacteria often cause extensive damage to agriculture. So, there is a need of insecticides, fungicides, antibiotics for use on animal and plant productions. Generally, synthetic substances are utilized as the main control methods. However, the increased residual toxic of these substances in food and the occurrence of resistance by agents have been a serious problem to be solved. As natural substances are relatively less damaging to the mammalian health and environment, they may be good alternatives to the synthetic ones and are of considerable interest and economic importance. Artemisia species have shown potential in use against stored product insects, phytopathogenic and toxigenic fungi, arthropods, and as phytotoxic. The main chemicals constituents isolated from Asteraceae genera are flavonoids, and their essential oils are mainly constituted of camphor, 1,8-cineole, borneol, terpinen-4-ol, bornyl acetate, thujone. This review reports the constituents and biological activities of the Artemisia species and their possible use in animal and plant health.

Nutrigenomics studies the impact of nutrients on genome and response of individual genetic makeup to diet. On the other hand nutrigenetics studies the impact of nutrient on a single gene. Some single nucleotide polymorphisms (SNPs) are determinants of individual requirement of nutrients but some others may be responsible for causing diseases. System biology approach is mainly used in nutrigenomics whereas individual nutrition is the major subject of nutrigenetics. Diet active molecules and human genetics are two major factors which govern the development of chronic diseases, namely cancer, cardiovascular diseases, diabetes, hypertension and obesity. Adequate and proper amount of nutrients prevent us from developing chronic diseases. The nutrients should keep desired balance between total oxidation status and total antioxidant response of the genome to maintain a balanced level between these two variables. If this balance is disturbed by our eating habits, our genomic system may become prone to development of chronic diseases. Nutrigenomic approach for control of such diseases is to enhance antioxidant status of body by supplementing food with antioxidants which become deficient in a diseased person.