Marisia - Maros Megyei Múzeum Évkönyve 35/2. (2015)
Zoology
S. NEAGU, R. COJOC, M. ENACHE, I. GOMOIU, G. GHEMES, A. GHEORGHE, M. TUDORACHE In order to investigate the ability of the selected halophilic bacterial cells to use various types of waste glycerol, the culture media MH or R-Agar, in the case of the Marinococcus halophilus strain were supplemented with 1% tested waste glycerol. The composition of R-agar culture medium is (g/1): NaCl — 5, Peptone — 10, Casamino acids - 5, Malt extract — 5, Yeast extract - 5, Beef extract - 5, MgSO/( x 7H,0 - 1 and Tween 80 - 50 pi. The medium pH before autoclaving was 7.2. The growth of Marinococcus halophilus on several waste glycerol type-Sunflower oil -Rapeseed oil Palmier oil Cultivation time (hours) (a) (b) Fig. 2: The growth of the investigated strains on culture media supplemented with 1% from various types of waste glycerol The data represented in figure 2 suggested the ability of M. halophilus strain to use for growth the waste glycerol resulted from biodiesel of sun flower oil, rapeseed oil and palmier oil. In the first 72 hours of cultivation (at 37°C and stirring at 150 rpm) the growth curve is similar in all investigated glycerol samples (Figure 2a). After this period the optical density decreased in case of cultivation on media supplemented with rapeseed oil. A similar behavior has been recorded in case of the investigated wild bacterial cells cultivated on media supplemented with waste glycerol from Slobozia source (Fig. 2c). According to manufacturer data these residual glycerol contains some organic matter, phosphate salts and potassium salts as a consequence of biodiesel obtaining protocols. These residual matters could be a factor for the growth behavior of the investigated strains. On the other hand, on the media supplemented with waste glycerol obtained from Medias source the strain 5-1, which showed Gram negative staining (Table 1) had no ability to grow (Figure 2b). For the other four tested strains the optical density increased for 48 hours of cultivation and after this period remained relatively constant (Figure 2b). These answers 70 I Очо 40 ►>-» 'Iг> TJ ~rtо О О 24 48 72 96 144 Cultivation time (hours) The growth of halophilic bacterial strains on media supplemented with waste glycerol (Medias source) The growth of halophtlic bacterial strains on media supplemented witli waste glycerol (Slobozia source) I О40 40 'S 'Sн vтз ао • *-н Cultivation time (hours)
