Frontiers of Agriculture and Food Technology

Frontiers of Agriculture and Food Technology ISSN 7295-2849 Vol. 2 (6), pp. 001-004, June, 2012. © International Scholars Journals

Full Length Research Paper

Dechlorination of 1,2– dichloroethane by Pseudomonas aeruginosa OK1 isolated from a waste dumpsite in Nigeria

A. I. Okoh¹*, A. O. Olaniran^1,2 and P. Golyshin³

¹Department of Microbiology,Obafemi Awolowo University, Ile - Ife, Nigeria.

²Department of Microbiology, University of Durban-Westville, Durban,South Africa.

³Molecular microbial ecology lab, German Research Center for Biotechnology, Braunschweig, Germany.

Accepted 19 March 2012

Abstract

As part of our attempt at isolating and stocking some indigenous microbial species, we isolated a bacterium from a waste dumpsite with appreciable dechlorination activity. 16S rDNA profiling revealed the isolate to be a strain of Pseudomonas aeruginosa and the sequence has been deposited in the NCBI nucleotide sequence database (accession number AJ550306). The bacterium utilized 0.1% (v/v) 1, 2 – dichloroethane (1, 2 – DCE) as sole source of carbon and attained peak cell density of 6.0 × 10 ⁷ cfu/ml in 48 h. It also has a proportionate increase in chloride release during this period resulting in the release of 80% free Cl^-. The bacterium also had dehalogenase activities against other chlorinated organics such as monochloroacetic acid, trichloroacetic acid, dichloromethane, trichloromethane and tetrachloromethane at pH 7.5 and 9.0. Optimum temperature for dehalogenase activity against 1, 2 – DCE was 35^oC.

Key words: Dechlorination, 16S rDNA, bioremediation, Pseudomonas aeruginosa OK1.

Frontiers of Agriculture and Food Technology ISSN 7295-2849 Vol. 2 (5), pp. 001-005, May, 2012. © International Scholars Journals

Full Length Research Paper

Hydrogen as clean fuel via continuous fermentation by anaerobic photosynthetic bacteria, Rhodospirillum rubrum

Ghasem Najafpour*, Ku Syahidah Ku Ismail, Habibollah Younesi, Abdul Rahman Mohamed and Azlina Harun Kamaruddin

School of Chemical Engineering, Universiti Sains Malaysia, Penang, Malaysia.

Accepted 10 March, 2012

Abstract

Hydrogen has been considered a potential fuel for the future since it is carbon-free and oxidized to water as a combustion product. Bioconversion of synthesis gas to hydrogen was demonstrated in a continuous fermentation utilizing malate as a carbon source. Rhodospirillum rubrum, an anaerobic photosynthetic bacterium catalyzed water gas shift reaction which was used in this research. The synthesis gas (CO) was used as a source of energy along with tungsten light supplied for growth and bioconversion of the photosynthetic bacteria. The microbial process in fermentation media was carried out in continuous culture to observe the effect of light intensity, agitation and liquid dilution rate on hydrogen production. The maximum hydrogen yield at 500 rpm was 0.65 mmol H₂/mmol CO. Desired media flow rate was preferable for high hydrogen production. At 0.65 ml/min media, hydrogen was produced at 7.2 mmol/h. This new approach, use of biocatalyst, can be considered as an alternative method to the conventional Fischer Tropsch synthetic reactions, which were able to convert synthesis gas into hydrogen.

Key words: Hydrogen, syngas, continuous bioreactor, Rhodospirillum rubrum, light intensity, agitation rate and flow rate.

Frontiers of Agriculture and Food Technology ISSN 7295-2849 Vol. 2 (5), pp. 001-008, May, 2012. © International Scholars Journals

Review

Applied genomics in the improvement of crops grown in Africa

Jonathan H. Crouch¹* and Rodomiro Ortiz²

¹International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Andhra Pradesh, India.

²International Institute of Tropical Agriculture (IITA), Eastern & Southern Africa Regional Centre (ESARC), P.O. Box 7878, Kampala, Uganda.

Accepted 15 March, 2012

Abstract

Crop biotechnology seems to be in its infancy in Africa, some national researchers are well trained in this area but lack of funding from their national governments does not allow them take advantage of their knowledge and professional skills. Among the agro-biotechnology tools, tissue culture ranks first in the micro-propagated and tree crops. DNA marker-aided breeding for a range of traits (particularly to overcome diseases and pests or low input environments) should become the second most important application of agro-biotechnology in the mid-term. Molecular markers are being used worldwide to tag specific chromosome segments bearing the desired gene(s) to be transferred (or incorporated) into breeding lines (or populations). In this way, indirect selection with co-dominant molecular markers tightly linked to the gene(s) controlling the characteristic(s) of interest improves response to selection, because heritability for co-dominant markers equals to 1. Molecular markers are therefore descriptors that offer reproducible results for characterizing genotypes. Similarly, applied plant genomics also improves the understanding of crop gene pools, which are being enlarged by including transgenes and “native” gene pools. Furthermore, finding new genes adds value to traditional agricultural products. There are many on-going applications of DNA markers in research-for-development and crop improvement for crops grown by African farmers. Marker-assisted selection and –aided introgression are being employed by private and public plant breeders mostly to locate and select genes for controlling important quality and disease or pest resistant traits.

Key words: Genomics, crops, biotechnology, breeding, Africa.

Frontiers of Agriculture and Food Technology ISSN 7295-2849 Vol. 2 (5), pp. 001-006, May, 2012. © International Scholars Journals

Full Length Research Paper

Expression of a 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene in peach (Prunus persica L.) fruit in response to treatment with carbon dioxide and 1-methylcyclopropene: possible role of ethylene

Francis M. Mathooko^1,*, Yuki Tsunashima², Yasutaka Kubo² and Akitsugu Inaba²

¹Department of Food Science and Technology, Faculty of Agriculture, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000, Nairobi 00200, Kenya.

²Laboratory of Postharvest Agriculture, Faculty of Agriculture, Okayama University, Tsushima, Okayama 700-8530, Japan

Accepted 14 March, 2012

Abstract

In this study we investigated the effect of exogenous ethylene treatment on ethylene production, 1-aminocyclopropane-1-carboxylate (ACC) oxidase activity and expression of an ACC oxidase (PP-ACO1) gene previously cloned (Mathooko et al., 2001) in peach (Prunus persica L.) fruit. We also investigated the mode of action of CO₂ and 1-methycyclopropene (1-MCP) in the regulation of ethylene biosynthesis during peach fruit ripening. Fruits were treated with various concentrations of ethylene (0.1, 1, 10, 100, 500, 1000 ppm) and also with CO₂ and 1-MCP in the presence or absence of 500 ppm ethylene. Ethylene stimulated ethylene production at concentrations of 100 ppm and above while ACC oxidase activity was stimulated in a concentration-dependent manner. PP-ACO1 was slightly constitutively expressed and exogenous ethylene stimulated accumulation of its mRNA transcript in a concentration-dependent manner up to 100 ppm after which the level remained constant. CO₂ and 1-MCP inhibited the ethylene-stimulated ethylene production, ACC oxidase activity and accumulation of PP-ACO1 transcripts by about 50%. These results indicate that ethylene plays a key role in the regulation of ethylene production and ACC oxidase activity and its gene expression in peach fruit. Further the results indicate that CO₂ and 1-MCP regulate ethylene biosynthesis in peach fruit during ripening, at least in part, by antagonizing ethylene action.

Key words: ACC oxidase, carbon dioxide, ehylene, 1-methylcyclopropene, peach, Prunus persica.