Marisia - Maros Megyei Múzeum Évkönyve 35/2. (2015)

Zoology

of the strain 5—1 could be associated either to the chemical composition of cell membrane or the presence of other compounds in tested glycerol as manufacturer described. On the other hand, the putative effect of glycerol as osmoprotective agent or its effect as compatible solut (Poolman and Glaasker, 1998) should not be excluded.

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The growth of halophilic microorganisms in the presence of-waste glycerol and its conversion in glycidol

Fig. 3: GC-FID analysis of the reaction mixture pointing out the presence of glycerol carbonate and glycidol as the reaction products of glycerol biotransformation.

Table 2 — The presence of glycidol and glycerol carbonate in biomass or supernatant of M. halophilus and strain 1—9. The table revealed the presence of GlyD and GlyC in liquid culture after cultivation of several halophilic microbial cells; a = supernatant; b = liquid culture.

Investigated sample Glycidol Glycerol Other com(GlyD) carbonate pounds

_________________________________________________________________________(GlyC)_________________

Biomass from Marinococcus halophilus R-AGAR 5% NaCl____________ - + +

Biomass from strain 1—9 on MH media with 10% NaCl___________ +

Supernatant from Marinococcus halophilus R-AGAR 5% NaCl (a) + +

Supernatant from strain 1—9 on MH media with 10% NaCl (a)________ + +

Supernatant from Marinococcus halophilus R-AGAR 5% NaCl (b) + + +

Supernatant from strainl—9 on MH media with 10% NaCl (b)_______ + + +

The GC-FID investigations on biomass or supernatant resulted from cells centrifugation for 10 minutes at 9500 rpm revealed in all tested strains either the presence of glycidol and glycerol carbonate or other compounds resulted from the enzymatic conversion of waste glycerol to these chemical structures. According to the date showed in table 2 the glycidol can be produced in the presence of supernatant of the strain 1-9 cultivated in MH with 10% NaCl and supernatant of the strain M. halophilus cultivated in R-agar media with 5% NaCl. On the other hand the glycerol carbonate correspond to the biomass of M. halophilus cultivated on R-agar medium with 5% NaCl and strain 1-9 cultivated on MH media containing 10% NaCl (Table 2, Figure 3).

The results revealed the ability of the investigated halotolerant and moderately halophilic bacteria isolated from saline and hypersaline environments from Romania to convert waste glycerol in value-added products, e.g. glycerol carbonate and glycidol.

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