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A . G ES S ES SE A ND B. A . G AS H E.1997. An alkaline xylanase-producing alkaliphilic Bacillus sp. AR-009 was isolated from an alkaline soda lake in Ethiopia. The enzyme was optimally active at pH 9 and was stable over a broad pH range. The optimum temperature for xylanase activity, assayed at pH 9, was 60°-65°C. Measured at pH 8 and 9, the enzyme had good stability at 55°and 60°C. At both pH values, over 80% of its original activity was retained after heating for 2·5 h at 55°C. At 60°C, the enzyme maintained 63% of its original activity after 2·5 h incubation while at pH 9 it retained 54% of its original activity after 1 h heating. These properties qualify the enzyme to be novel and potentially important for application in some industrial processes.

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Kocho, an acidic starchy food, is prepared by fermenting a mixture of the scraping of the trunk and pulverized stem and corm of ensette (Ensette ventricosum). Leuconostoc mesenteroides is responsible for initiating the fermentation. Because of the activities of this species and, to some extent, of Streptococcus faecalis, the pH of the fermenting kocho was reduced from 6˙5 to 5˙6. These organisms were then succeeded by the homofermentative bacteria Lactobacillus coryneformis subsp. coryne‐formis and Lact. plantarum. Through the activities of the Lactobacillus species, the pH was further reduced to 4˙2. Pediococcus cerevisiae, although present in kocho, did not achieve prominence because of the relatively low fermentation temperature (14°‐18°C). Spore‐formers were present in fairly high numbers during the first 15 d of fermentation. It was suspected that the butyrous odour which was detected during the first 2 weeks in fermenting kocho might be due to the activities of certain clostridial species. Yeasts were also present in fairly high numbers.

in 2.7% of the samples analysed. The enteric Ad (types 40 and 41) were detected in 2% of the samples and the remaining 5.8% of Ad positive samples were non-enteric Ad. An increase of RV was noted in the autumn-winter season but no seasonal pattern was observed in Ad shedding. Seasonal prevalence of AsV could not be determined. The average age of children infected with these agents was less than one year. Conclusion: The incidence of rotavirus infection amongst children in Botswana appears to be relatively low. The prevalence rate of adenovirus and astrovirus is similar to other studies in parts of Southern Africa. However, continued enteric virus surveillance and epidemiology amongst this group is required.