Resumo

The sugarcane sector presents great economic importance to Brazil, producing ethanol and sugar, but also a great amount of wastewater. This is highly polluting organic load, rich in lignocellulose and phosphorous. Under anaerobic conditions, some bacteria release the phosphorus stored in the form of polyphosphate due to the need to store carbon in the form of poly-βhydroxybutyrate (PHB), requiring the presence of a source of easily degradable carbon such as acetate. Then, they activate acetyl Co-A, the synthesis of PHB and poly-valerate, the degradation of glycogen and polyphosphate, and, finally, the simultaneous release of ortophosphate, potassium and magnesium. When the concentration of readily biodegradable substrate is low in the aerobic zones, these organisms begin to degrade PHB, and part of the released energy is used to form and store poly-p, removing phosphorus from the water. In this study, different heterotrophic bacteria able to remove poly-p were selected using standard methods of isolation and enrichment, from a sugarcane-washing water of a treatment plant of an agro-industry in the Northeastern Brazil. This was responsible for milling 3.2 million tons of cane, and generate 21.6 billion liters of effluent in the season of 2012/2013. The bacteria were identified mainly using the biochemical tests API 20E and 20NE, and investigated as their ability to accumulate polyphosphate (confirmation by the Neisser staining) and reduce the chemical oxygen demand (COD), phenols, carbohydrates, and color of the effluent (APHA, 1995). The isolates with the best performance to reduce the analyzed parameters were Acinetobacter sp., Arthrobacter sp. and Pseudomonas sp., that combined with three filamentous fungi, after negative response in antagonism tests, showed removal of the color, phenols, carbohydrates, phosphorous and COD in rates respectively of 85%, 56%, 60%, 65% and 71%, after 7 days of incubation at 28ºC.