TABLE 3.

PBR ground experiments on algae and cyanobacteria, fed by a nitrifying culture.

Organisms	Hardware	Gas exchange	Volume	Light intensity	Mode	Duration	Results	Authors
Limnospira indica PCC 8005, fed by Nitrosomonas europaea ATCC 19178, Nitrobacter winogradsky ATCC 14123	PBR, 2 identical cylinders	External loop airlift	7 L and 77 L	white halogen lamps (20 W), between ≈ 100–400 W/m2 (≈ 460–1,840 μE m–2 s–1)	Continuous	4 years, many different experiments and conditions	The separately operated as well as the interconnected bioreactors were successfully run in a continuous way	Gòdia et al. (2002)
Axenic Limnospira indica, fed by 12 different nitrifying inocula	Two membrane bioreactors (nitrifying community), 96-well plate (L. indica)	Air pump	8 L (bioreactor), 0.3 mL (L. indica) and 0.8 L (L. indica)	200 μE m–2 s–1 (0.3 mL batch of L. indica), 160 μE m–2 s–1 (0.8 L batch of L. indica)	Batch and continuous	0.8 L batches of L. indica: 10 days, bioreactor up to 180 days (diagram)	Limnospira indica grew with high rates on the nitrified urine and yielded a high biomass protein content. Nitrobacter spp. became the dominant species in the nitrite oxidizing community	Coppens et al. (2016)
Different microalgae species, fed by commercially available nitrifying activated sludge	Plexiglas, gastight PBR	Airlift	4 L	300 μE m–2 s–1	Semi-continuous	180 days	The biological oxidation of all nitrogen sources in urine was successful and is a promising treatment for nutrient recovery of waste water	Muys et al. (2018)