A thermostable amylase, possibly a 3-amylase from Thermoactinomyces sp. no. 2 isolated from soil, is reported. The enzyme was purified 36-fold by acetone precipitation, ion-exchange chromatography, and Sephadex G-200 gel filtration, and the molecular weight was estimated at 31,600. The enzyme was characterized by demonstration of optimum activity at 60°C and pH 7 and by retention of 70% activity at 70°C (30 min). It was stimulated by Mn2+ and Fe2+ but strongly inhibited by Hg2 Maltose was the only detectable product of hydrolysis of starches and was quantitatively highest in plantain starch hydrolysate.

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The Salmonella, Arizona, Shigella and Aeromonas contents of 39 snails (Achatina achatina) were investigated. Serotyping of the Salmonella isolates revealed the presence of S. manhattan, S. ndolo, S. reading, S. uppsala, and S. typhimurium. Six of 18 Shigella isolates were identified as Sh. sonnei while all the Aeromonas proved to be A. hydrophila. Fifty eight percent of these A. hydrophila isolates were enterotoxigenic, and their toxin was shown to be heat labile. All the A. hydrophila strains were both protease positive and haemolytic: 66.7% being both alpha and beta haemolytic while 33.3% showed only alpha haemolysis.

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The effects of two extractants on the activities of carboxypeptidase and proteinase enzymes from three sorghum varieties germinated for 3 and 5 days were studied. In all three varieties, cysteine hydrochloride (Cyst. HCl) proved a better extractant than 2-mercaptoethanol (2-ME) as shown by the increase in carboxypeptidase and proteinase activities with 5-day malts. A three-way analysis of variance (ANOVA) on the effect of germination time, extractant and variety on the carboxypeptidase activities of the three malts showed that all the factors plus their possible fourway interactions highly significantly (P < 0.001) affected the extractability/activity of the enzyme. However, while the three factors had a highly significant (P < 0.001) effect on the proteinase activity, one of their four-way interactions, specifically, extractant/variety, had no significant effect. This suggests that, unlike the carboxypeptidase enzyme, the effectiveness of the extractants in enhancing the extractability/activity of the proteinase enzyme in all the sorghum malt samples was amongst other factors, not variety-dependent.