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We have established a system for hydrogen (H2) production from algal starch via lactic acid using a mixed culture of a lactic acid bacterium, Lactobacillus amylovorus, and a photosynthetic bacterium, Rhodobium marinum A-501. We found that the H2 production from lactate was stimulated in the presence of algal extract, which was obtained from algal biomass homogenate used as a substrate in the system by removing settleable solids including starch. To analyze the stimulating effect of algal extract on H2 production, we developed a kinetic model for H2 production by R. marinum A-501. The model revealed that approximately 20% of lactate was consumed for cell mass production, and the remaining portion was a source of reducing power to drive hydrogen production or other cellular processes. In the presence of algal extract, the model indicated that the conversion efficiency from lactate to the reducing power increased from 0.56 to 0.80 and nitrogenase activity increased up to twofold, resulting in the increase in yield of hydrogen from lactate from 29% to 48%. These results suggest that algal extract can attenuate the limitation process in lactate catabolism by which the supplementation of reducing power to drive H2 production was suppressed. [ABSTRACT FROM AUTHOR]

Summary: The unique metabolic profile of cancer (aerobic glycolysis) might confer apoptosis resistance and be therapeutically targeted. Compared to normal cells, several human cancers have high mitochondrial membrane potential (ΔΨm) and low expression of the K+ channel Kv1.5, both contributing to apoptosis resistance. Dichloroacetate (DCA) inhibits mitochondrial pyruvate dehydrogenase kinase (PDK), shifts metabolism from glycolysis to glucose oxidation, decreases ΔΨm, increases mitochondrial H2O2, and activates Kv channels in all cancer, but not normal, cells; DCA upregulates Kv1.5 by an NFAT1-dependent mechanism. DCA induces apoptosis, decreases proliferation, and inhibits tumor growth, without apparent toxicity. Molecular inhibition of PDK2 by siRNA mimics DCA. The mitochondria-NFAT-Kv axis and PDK are important therapeutic targets in cancer; the orally available DCA is a promising selective anticancer agent. [Copyright &y& Elsevier]