Conference Book of Abstracts - Taita Taveta University College

The Soda Lakes of Kenya have attracted much interest from researchers over the years. They areamong the most productive ecosystems in the world with a primary productivity of 10g cm -2 day -1 and are very rich in microbial diversity. Due to the highly extreme conditions of pH,temperature and salinity, microorganisms from soda lakes have great promise for exploitation inBiotechnology. Using a combination of culture dependent and culture independent techniques,the microbial diversity of several soda lakes was explored. Clone Library studies of LakeElmenteita using bacterial and archeal primers revealed major groups of bacteria and archaea. Aclone library of bacterial 16S rRNA genes revealed the presence of 37 orders in the DomainBacteria. Cyanobacteria were the most abundant clones followed by the phylum Firmicutesgroup. The firmicutes had the most diverse genera represented. All clones affiliated to the classBetaproteobacteria originated from DNA obtained from the water samples. BLAST analysisshowed that 93.1% of the sequenced clones had similarity values below 98% to both culturedand as yet uncultured bacteria. Comparative sequence analysis of archaeal clones affiliated themto a wide range of genera including Natronococcus, Halovivax, Halobiforma, Halorubrum, andHalalkalicoccus. The highest percentage (46%) of the clones, however, belonged to unculturedmembers of the Domain Archaea in the order Halobacteriales. In a recent study, water, wetsediments, dry sediments, mats and grassland soil were collected at different sampling pointsfrom lakes Bogoria, Magadi, Crater lake Sonachi and Elmenteita in Kenya. The V3 to V5 regionof the 16S rRNA gene was analyzed using 454 pyrosequencing-based approach to assess thebacterial and archaea diversity in the collected samples. Within the domain Bacteria, a total of 47phyla were detected. A total of 198 cultured genera were represented in the bacteria dataset. Inthe domain Archaea, the Crenarchaeota and Euryarchaeota were predominant. The PhylumKorarchaeota was detected only in the dry sediments from Lake Bogoria (sample Arc-17B). In13 samples, the Halobacteria were the most abundant while classes Thermoplasmata andMethanomicrobia. A total of 30 cultured genera were represented in this dataset. Rarefactionanalysis shows that the water samples and the samples from Lake Magadi were the least diversein terms of the number of species. The low diversity in the Magadi samples may be attributed tothe high salt and pH which may promote growth of specific group of organisms that haveadapted to the harsh conditions. Isolation of bacteria and fungi from Lake Magadi, Elmenteitaand Nakuru led to the recovery of previously isolated as well as yet unrecovered groups. Novelspecies are in the process of being described. The results show that the archaeal and Bacterialdiversity in the Soda Lakes could be higher than previously reported.ReferencesMwirichia, R, Cousin, S; Muigai, AW, Boga HI and Stackebrandt, E (2010) Bacterial Diversity in the HaloalkalineLake Elmenteita, Kenya. Curr. Microbiol. 62(1):209-21Mwirichia, R, Muigai, AW, Tindall, B, Boga HI and Stackebrandt, E (2010) Isolation and characterization ofbacteria from the haloalkaline Lake Elmenteita. Extremophiles 14(4):339-48Mwirichia, R, Cousin, S; Muigai, AW, Boga HI and Stackebrandt, E (2010): Archaeal Diversity in the HaloalkalineLake Elmenteita in Kenya. Curr. Microbiol. 60:47–52Kambura AK (2011) Isolation,characterization and screening of bacterial isolates from lake Magadi for Exoenzymesand Antimicrobial Activity. MSc Thesis, Jomo Kenyatta University of Agriculture and Technology, Kenya