The residual crude glycerol enhancement of the ammoniacal nitrogen bioremediation by microalgae and bacteria consortium with concomitant production of PHAS and pigments of industrial interest

The landfill leachate and industrial effluents (farm of swine, poultry, cattle, distilleries, etc.) present concentrations above 800 mg.L-1 of ammoniacal nitrogen. The absence of economically viable processes for its removal has led to the loss of the water body potability. An innovative bioprocess was developed for the bioremediation of NH3. The residual crude glycerol from biodiesel production was innovatively used in a mixed culture of heterotrophic bacteria and cyanobacteria to reduce the NH3 toxicity and enhance the consumption of the NH3. >600 mg.L-1 of NH3 (consumption of 100 mg.L-1.d(-1)) was consumed in just 8 days, with efficiency of 100 % approximately. Also, there was a promising production of compounds of industrial interest by these microorganisms: polyhydroxyalkanoates (PHAs) for biodegradable plastics by heterotrophic bacteria (132 +/- 19 mg.g(-1)); pigments by A. platensis (phycocyanin: 84.2 +/- 2.8 mg.g(-1) and total carotenoid: 1.62 +/- 0.18) and proteins (38 +/- 2 %)., with a maximum biomass productivity of 0.435 +/- 0.004 mg.L-1.d(-1).

Automated summary

The concentrations of ammoniacal nitrogen in landfill leachate and industrial effluents are high, leading to non-potability of the water. An innovative bioprocess utilizing residual crude glycerol from biodiesel production and a mixed culture of bacteria was developed to reduce the toxicity of ammonia and enhance its consumption. This approach also showed potential for the production of industrially valuable compounds.