Improving biomass resource recycling capacity of Rubrivivax gelatinosus cultivated in wastewater through regulating the generation and use of energy

Abstract

This paper investigated Mg²⁺ enhancement of biomass production through regulating the generation and use of energy in Rubrivivax gelatinosus wastewater treatment. Results showed that proper Mg²⁺ dosage range was 1.5–15 mg/L. With optimal Mg²⁺ dosage (10 mg/L), biomass production (5010 mg/L) was improved by 60%. Both protein and chemical oxygen demand (COD) removals reached above 90%. Biomass yield improved by 38%. Hydraulic retention time was shortened by 25%. Mechanism analysis indicated that as activator, Mg²⁺ promoted specifically isocitrate dehydrogenase (IDH) and Ca²⁺/Mg²⁺-ATPase activities in energy metabolism, and then improved the generation of adenosine triphosphate (ATP) and the use of ATP. This enhanced the secretion and activity of protease, protein and COD removals, and then led to more biomass production. With 10 mg/L Mg²⁺, IDH and Ca²⁺/Mg²⁺-ATPase activities, ATP production, protease activity were improved by 43.8%, 40.6%, 39.4% and 46.5%, respectively.

Keywords:

• R. gelatinosus
• Mg²⁺
• biomass production
• biomass resource
• wastewater treatment
• energy metabolism

Acknowledgements

The authors are grateful for the financial support from National Natural Science Foundation of China.