Light And Oxygen Impelling Rubrivivax Gelatinosus Directly Used Food Processing Wastewater To Accumulate Poly-β-Hydroxybutyrate, 5-Aminolevulinic Acid, Pigment

Abstract Background: Rubrivivax gelatinosus have the advantage of using wastewater to realize biomass recovery. However, they still cannot be large-scale applied because they cannot directly treat the wastewater containing macromolecular organics. Thus, this paper investigated the effect of light-oxygen condition on Rubrivivax gelatinosus (R. gelatinosus) directly recycling wastewater containing macromolecular organics to produce biomass, poly-β-hydroxybutyrate (PHB), 5-Aminolevulinic acid (5-ALA), pigment.Results: R. gelatinosus directly treated the macromolecules organic (soybean protein and starch) wastewaters and achieved biomass recovery under light-anaerobic and light-micro oxygen in six conditions. COD, protein, starch removals for two wastewaters all reached above 70%. Renewable bio-resource such as biomass, PHB, 5-ALA, pigment productions were 10 times of initial content. Theoretical analysis indicated that light activated two component signal pathway by stimulating its first hk gene expression, which regulated synthesis of protease and amylase. However, oxygen concentration decided the level of gene expression and the amount of enzymes. When oxygen was at micro-oxygen or anaerobic, above these expression and synthesis were conducted. Conclusion: In summary, this study expanded the view point ignored by traditional theory. It was realized that PNSB directly treated wastewater and accumulated nutrients (biomass, PHB, pigment and 5-ALA) for recycling, which reduced the secondary pollution of excess sludge to the environment.