Abstract

AREVALO STEVENSON, Raymundo Alfredo; SARMA, S.S.S.  and  NANDINI, S.. Population dynamics of Brachionus calyciflorus (Rotifera: Brachionidae) in waste water from food-processing industry in Mexico. Rev. biol. trop [online]. 1998, vol.46, n.3, pp.595-600. ISSN 0034-7744.

Waste water from Mexico's largest food processing industrial sector (based on maize, nejayote water) was used for growing Brachionus calyciflorus isolated from Lake Chapultepec in the Federal District of Mexico (D.F.). Nejayote water was collected from Colonia Providencia, D.F. Experiments were conducted at 25°C in 25 ml capacity vials with 20 ml of medium into which we introduced B. calyciflorus at an initial density of 1 ind ml^-1. The experimental design consisted a total of 33 test vessels (2 food combinations X 5 densities X 3 replicates = 30 plus 3 replicates as controls that contained only algae). Experiments were terminated after day 16. Waste water in original concentration did nt rotifes. However, when diluted to 5 oncentrations (ranging from 2% to 32% and pH adjusted to 7.0), rotifer density increased with increasing concentration of waste water. Green algae (at constant density of 2 X 10 6 cells-1 of Chlorella) in combination with waste water resulted in a higher abundance of rotifers only at higher concentration (above 8 %) of waste water. The maximum peak density of rotifers (238-50 ind ml -1) was obtained at 16% dilution of waste water nd with addition of Chlorella. The rate of population increase per day ® (mean-SD) varied from 0.355-0.059 to 0.457-0.048 depending on food combination and concetration.

Keywords : Rotifer; Brachionus; waste water; population growth; Mexico.