Cyanobacteria cultivation using olive milling wastewater for bio-fertilization of celery plant

Abstract

Olive milling wastewater is a major problem facing the Mediterranean countries producing olive oil like Egypt. In the present study, olive milling wastewater rich with organic phenolic compounds, macro and micro nutrients was used as growing media for cyanobacteria. The cyanobacteria were grown on wastewater to obtain two biofertilizers, one bioformulated from single culture of <em>Spirulina platensis</em> and the second from mixed culture of <em>S. platensis, N. muscorum and A.oryzae</em>. The produced biofertilizers, were applied on a sandy soil to grow celery plant under different levels (25, 50 and 75%) of the recommended chemical fertilizers, while the control did not receive any fertilizers in a greenhouse experiment at Giza Research station, Agricultural Research Center, Egypt during the summer season of 2018. Results indicated that application of biofertilizers led to a significant (p<0.05) increase in the height of plant, root and stem lengths over the control group. The number of leaves per plant as well as chlorophyll content were highest in the treatments of Bio-Mix 25 and 50%. Also, these treatments increased the total macro- and micro-nutrients of celery. There was very remarkable enhancement in some recorded sandy soil properties after harvest i.e., pH, total organic matter, total nitrogen, phosphorus and potassium by the treatments of Bio-Mix with 25 and 50%. The present study concluded that 1/4 or 1/2 of the recommended dose of NPK fertilizers could be saved for celery growth by using Bio-Mix product from cyanobacteria and olive milling wastewater as a promising eco-friendly bio-organic fertilizer.