Phototrophic polypeptide production from urine

Project

Phototrophic polypeptide production from urine

Human urine is rich in polluting nutrients (nitrogen). Cyanophycin is a nitrogen rich polymer produced by cyanobacteria. In this project we will explore the possibility to grow cyanobacteria on urine while producing cyanophycin.

Introduction

Human urine has high nutrient content, containing up to 80% of the nitrogen (N) and 40% of the phosphorus (P) that end up in household wastewater, while accounting for only 1% of its volume (Kujawa-Roeleveld & Zeeman, 2006). Microalgae have previously been shown to grow in undiluted urine when employing high light supply rates and short light path photobioreactors, making it possible to recover most of these nutrients in form of biomass (Tuantet et al., 2014). However, the N:P ratio of urine (30-47:1) limited microalgae growth along with the recovery of N.

The phosphorus limitation could be overcome by cyanobacteria, which accumulate a storage material called Cyanophycin Granule Polypeptide (CGP) when facing P limitation. CGP has potential applications as dispersant and as a raw material for bioplastics production (Joentgen, et al., 2001). In this context, the production of cyanobacterial biomass on source-separated urine could make it possible to fully recover these nutrients, and even transform a significant fraction of them into useful products for industry, contributing to a circular economy.

Aim

The aim of this project is to grow cyanobacteria on urine and in this manner combine urine treatment with CGP production and biorecovery of nutrients. Additionally, phycobiliproteins and other compounds could be recovered as by-products.

Approach

In this project, it will be assessed if also cyanobacteria can be grown on minimally diluted urine while accumulating CGP. Furthermore, process control will be adjusted in order to maximize biomass production, CGP accumulation, and to improve nutrient removal. Additionally, the process will be described by means of a mathematical model as basis for a bioreactor design.

Thesis projects

Within this project there are possibilities for doing a BSc or MSc theses and internships. The thesis content can include modelling and/or lab-work. If you are interested in doing a BSc or MSc thesis, feel free to contact Sebastian Canizales.

Acknowledgments

This project is funded by Wetsus, the European Centre of excellence for sustainable water technology.