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Papermills in U.S. annually produce 3 million tons of sulfite waste liquor solids; other fractions of waste liquor are monomeric sugars and lignosulfonates in solution. Recovery of lignosulfonates involves precipitation and cross-linking of sulfonates to form useful solid ion-exchange resin. Contamination of sugars recovered from liquor is avoided by first converting them to ethanol, then removing ethanol by distillation.
Recent work is reviewed on some reactions that could have occurred on the primitive earth and that could have played a part in the evolution of a self-replicating system. The transition from the primitive atmosphere to the simplest replicating molecules is considered in four stages: (1) the formation of a 'prebiotic soup' of organic precursors, including the purine and pyrimidine bases and the pentose sugars; (2) the condensation of these precursors and inorganic phosphate to form monomeric nucleotides and activated nucleotide derivatives; (3) the polymerization of nucleotide derivatives to oligonucleotides; and (4) the complementary replication of oligonucleotides in a template-directed process that depends on Watson-Crick base pairing.