Three green algae, Chlamydomonas reinhardii, Chlorella vulgaris and Scenedesmus obliquus, and one blue-green alga, Anabaena cyclindrica, were grown in chemically defined media. All the algae examined contained folates, beta-carotene and vitamins C and E; several of the B-vitamins and vitamin A were found in varying amounts in some but not in all the algae examined. All the green algae secreted significant amounts of folate and biotin and all but Scenedesmus secreted pantothenate into their growth medium; Anabaena secreted folate and pantothenate.

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Clostridium thermocellum was shown to ferment glucose in a medium containing salts and 0.5% yeast extract. An active glucokinase was obtained with improved conditions for growth, assay, and preparation of cell extracts. Cell extracts appear to contain a glucokinase inhibitor that interferes with the assays at high protein concentrations. Glucokinase activity is stimulated about 60% by pretreatment with dithiothreitol. Little or no fructokinase or mannokinase activity was detected in cell extracts. The absence of glucokinase in mannitol-grown cells, the increase in glucokinase activity upon incubation of cell suspensions with glucose, and the lack of increase in activity when chloramphenical is added are evidence that glucokinase is an inducible enzyme. The following enzymes were detected in cell extracts (the enzyme activities are shown in parentheses are micromoles per minute per milligram or protein at 27 C): glucokinase (0.48), phosphoglucose isomerase (0.73), fructose 6phosphate kinase (0.24), fructose diphosphate aldolase (0.59), glyceraldehyde 3phosphate dehydrogenase (0.53), triose phosphate isomerase (0.13), phosphoglycerate kinase (0.20), phosphoglycerate mutase (0.20), enolase (0.28), pyruvic kinase (0.13), and lactic dehydrogenase (0.13). Glucose 6-phosphate dehydrogenase activity was absent or very low (0.0002) and 6-phosphogluconate dehydrogenase activity also was relatively low (0.015). From these data, it is proposed that carbohydrate metabolism in C. thermocellum proceeds by the Embden-Meyerhof pathway.

Acid and alkaline phosphomonoesterase ( PME ) activity of phosphorus-depleted Ochromona.s danica could be partially but not completely repressed by exogenous inorganic phosphate ( Pi). Acid and alkaline PME activities were found in the plasma membrane as well as the cytosol and acid PME was secreted in the cell's environment.The extracellular and surface PME could provide the necessary phosphate for the growth of phosphorus-depleted algae in the presence of organic phosphates; specific organic phosphates, glucose-l-phosphate (G-l-P) and glucose-6-phosphate (G-6-P), supported growth with small inocula, other organic phosphates were inactive.G-l-P and G-6-P induced almost double the normal PME secretion, and this extra secretion is shown to be sufficient to provide for the growth of phosphorus-depleted cells inoculated in relatively small numbers.

S U M M A R YIntra-and extracellular acid phosphatases were purified 88-and 65-fold respectively from photoheterotrophic Ochroi?zonas danica Pringsheim. The purified enzymes differed in heat inactivation, substrate specificity, and inhibition by several divalent cations and NaF. Intracellular enzyme lost only 30 0; of its activity by heating at 60 "C for 200 min whereas the extracellular enzyme lost 80 ;; . Both enzymes were active over a broad pH range from 2-2 to 5-2 and had an optimum pH of 4-8. Both had broad substrate specificity and differed in their relative ability to hydrolyse /I-glycerophosphate, phenolphthalein diphosphate, glucose-I -phosphate, fructose-I ,6-diphosphate, ADP and ATP. Both were inhibited by Co2+, Zn", Hg", Fe"+, arsenate, tartrate and fluoroacetate but differed in their inhibition by Cu2*, Hg2t and NaF. Intracellular acid phosphatase was more susceptible to inhibition by Hg2-f and NaF, while extracellular acid phosphatase was more susceptible to inhibition by Cu2+. p-Chloromercuribenzoate and urea had no effect on either enzyme's activity. EDTA stimulated the activity of both enzymes. The Kin for the intra-and the extracellular enzymes was 0.5 and 0.33 mM respectively with p-nitrophenyl phosphate as the substrate.