Abstract: A method for preventing activated sludge from losing its settling ability, which sometimes happens in solid/liquid separation in an activated sludge treatment of an aqueous organic waste and causes the so-called bulking and scumming of the sludge. This method involves adding either (a) a nonionic and/or an anionic surfactant, (b) a combination of a nonionic surfactant with a cationic surfactant of a form of quaternary ammonium salt or (c) a combination of a nonionic surfactant and a cationic surfactant of a form of a quaternary ammonium salt with a cationic organic flocculant, to the activated sludge treatment system.

Abstract: Flavine nucleotides, which are useful as ingredients of nutrient compositions, raw materials for various pharmaceutical products, biochemical research reagents and so on, are produced from flavine nucleotide precursors and ATP by utilizing cells or a culture of a microorganism which belongs to the genus Escherichia, Enterobactor or Pseudomonas and harbors a recombinant DNA comprising a vector DNA and a DNA fragment carrying the genetic information relevant to the synthesis of FMN and/or FAD, or treated cells or a treated culture of the microorganism.