The cell biomass accumulation was estimated by measurement of fresh (FW) and dry (DW) weights. Dry mass was determined after drying the cells at 60 ◦C to constant weight. Samples were collected at 2–3 days intervals during a 30-day period, and each point of the growth curve represents the mean of three independent determinations (flasks). Subcultures were carried out during the exponential growth phase.