Rhamnolipid biosurfactant production by Pseudomonas nitroreducens isolated from petroleum-contaminated soil was investigated. The effects of carbon, nitrogen and carbon to nitrogen ratio on biosurfactant production were examined using mineral salts medium as the growth medium. The tenso-active properties (surface activity and critical micelle concentrations of the produced biosurfactant were also evaluated. The best carbon source, nitrogen source were glucose and sodium nitrate giving rhamnolipid yields of 5.28 and 4.38 g l(-1), respectively. The maximum rhamnolipid production of 5.46 g l(-1) was at C/N (glucose/sodium nitrate) of 22. The rhamnolipid biosurfactant reduced the surface tension of water from 72 to ~37 mN/m. It also has critical micelle concentration of ~28 mg l(-1). Thus, the results presented in our reports show that the produced rhamnolipid can find wide applications in various bioremediation activities such as enhanced oil recovery and petroleum degradation.

Aim:To characterize field isolates of infectious bursal disease virus (IBDV) from outbreaks in nine states in Nigeria through reverse transcription polymerase chain reaction (RT-PCR) and sequence analysis of portions of the VP2 and VP1 genes and to determine the presence or absence of reassortant viruses.Materials and Methods:A total of 377 bursa samples were collected from 201 suspected IBD outbreaks during 2009 to 2014 from nine states in Nigeria. Samples were subjected to RT-PCR using VP2 and VP1 gene specific primers, and the resulting PCR products were sequenced.Results:A total of 143 samples were positive for IBDV by RT-PCR. These assays amplified a 743 bp fragment from nt 701 to 1444 in the IBDV VP2 hypervariable region (hvVP2) of segment A and a 722 bp fragment from nt 168 to 889 in the VP1 gene of segment B. RT-PCR products were sequenced, aligned and compared with reference IBDV sequences obtained from GenBank. All but one hvVP2 sequence showed similarity to very virulent IBDV (vvIBDV) reference strains, yet only 3 of the VP1 67 VP1 sequences showed similarity to the VP1 gene of vvIBDV. Phylogenetic analysis revealed a new lineage of Nigerian reassortant IBDV strains.Conclusion:Phylogenetic analysis of partial sequences of genome segment A and B of IBDV in Nigeria confirmed the existence of vvIBDV in Nigeria. In addition, we noted the existence of reassortant IBDV strains with novel triplet amino acid motifs at positions 145, 146 and 147 in the reassorted Nigerian IBDV.

Four sorghum varieties (SK 5912, KSV 4, KSV 8, ICSV 400) were malted and extracted under similar conditions to assess their quality for brewing. The results showed that, in general, the sorghum varieties had high malting loss which was attributed to the high germination temperature used. The sorghum varieties also developed low levels of amylolytic activity (␣-amylase and ␤-amylase), and with similar ratios. When the sorghum malts were mashed at different temperatures with the aid of commercial enzyme preparations, it was observed that mashing temperatures were more important in sugar release than additions of commercial enzymes. This was because at the lower mashing temperature, sorghum starch was not adequately gelatinised. However, when commercial enzyme preparations were added, low levels of enzymes were very effective in reducing wort viscosity and producing free amino nitrogen (FAN). Although, both commercial enzyme preparation and mashing temperature influenced sugar production, the malts produced glucose and maltose at similar ratios. Therefore good quality malts can be produced from sorghum, however mashing will employ commercial enzymes and mashing regimes are not yet optimised.

A medium was developed to obtain the maximum yield of raw starch-digesting amylase from Aspergillus carbonarius (Bainier) Thom IMI 366159 in submerged culture with raw starch as the sole carbon source. The amylase was puri®ed to apparent homogeneity by sucrose concentration and ion exchange chromatography on S-and Q-Sepharose (fast¯ow) columns. SDS-PAGE revealed two migrating protein bands corresponding to relative molecular masses of 31.6 and 32 KDa. The enzyme was optimally active at pH 6.0±7.0 and 40°C, was unin¯uenced across a relatively broad pH range of 3.0±9.0 and retained over 85% activity between 30 and 80°C after 20 min incubation. ), forming predominantly maltose and relatively smaller amounts of glucose.

Biochemical changes during fermentation of seeds of Prosopis africana for production of ogiri-okpei, a food condiment popular among people of West Africa were studied. Fermentation resulted in a net increase in concentrations of total soluble sugars and free amino acids, both reaching a peak after 72 h of fermentation but declining thereafter. Corresponding increases were observed in amylase and protease activities, respectively. Lipase activity was observed to be very strong, increasing throughout the duration of fermentation. Analyses of amino and fatty acid composition using an amino acid analyzer and gas liquid chromatography, respectively, revealed a wide variety of amino acids including glutamine > cystine > arginine and the fatty acids stearic > Arachidic > linolenic > linoleic in the unfermented seed in the highest concentrations. Fluctuations in the concentrations of these compounds were observed during the fermentation. At the end of 96 h fermentation, glutamine > cystine > lysine and an unidentified fatty acid > arachidic > linolenic acids were found in the highest concentrations. Marked increases in composition with increasing period of fermentation were observed for Ca, P, K, Mn, and Z. Transformations of amino acids, fatty acids, and minerals during the fermentation of this seed revealed during this study will contribute towards the development of an industrial process for ogiri-okpei as well as an understanding of its contribution to the nutrition of its consumers.