The supplied nutrient concentrations in the medium had a
strong influence on the biochemical composition of the
biomass. The carbohydrate concentration ranged from 18 to
40 % for Chlorella and from 13 to 44 % for Scenedesmus, indicating
that both species accumulated starch as a result ofnutrient starvation (Gonzalez-Fern andez and Ballesteros,
2012; Markou et al., 2012) (Fig. 4). For both species, the carbohydrate
concentration of the biomass decreased linearly with
increasing N supply in the medium (Table 1). In Chlorella, the
carbohydrate concentration also decreased (about 25%) with
increasing P supply (>2 mg P L1
) in the medium, but the
response was weaker when compared to that of N. For both
species, the FAME concentration responded in a quadratic
way to the N supply in the medium (Table 1), being highest
when N supply was lowest. The increase in FAME was mainly
due to an increase in C16:0 (palmitic acid) and C18:1 (oleic
acid).