Effects of different antibiotics and preservatives on Chlorella sorokiniana cell growth

ObjectiveEffects of different antibiotics and preservatives on growth of Chlorella sorokiniana cells were analyzed,and optimal antibiotics and preservatives and doses were screened to provide reference for establishing axenic culture of C. sorokiniana.MethodAntibiotics and preservatives were added in HSM media including chloramphenicol, streptomycin,penicillin,gentamicin and cefotaxime sodium(10,20,40,60,80 and 100μg/mL),potassium sorbate (50,100,150 and 200μg/mL),lactic acid bacteria(0.5%,1.0%and 2.0%),dimethyl fumarate(0.1,0.5,1.0,5.0, 10.0,25.0 and 50.0 μg/mL). Cell density,chlorophyll content and photosystem Ⅱ maximal photochemical efficiency (Fv/Fm)were determinated after 3 d cultivation.ResultCell density,chlorophyll content and Fv/Fm of C. sorokiniana were not significantly affected by 10-100 μg/mL penicillin and 10-80 μg/mL cefotaxime sodium(P>0.05 ,the same below). Adding 100μg/mL cefotaxime sodium inhibited cell growth with inhibition rate of 18.89%,and also decreased chlorophyll content and Fv/Fm extremely significantly(P<0.01,the same below). Compared with control,protein synthesis inhibitory antibiotics like chloramphenicol ,streptomycin and gentamicin were more toxic to C. sorokiniana. Strepto-mycin and gentamicin with concentrations over 10 μg/mL and chloramphenicol with concentrations over 20μg/mL had extremely significant inhibition effects on cell growth ,and the corresponding chlorophyll content and Fv/Fm dropped extremely significantly. Among the three preservatives,potassium sorbate did not affect C. sorokiniana cell growth sig-nificantly. Furthermore,the chlorophyll content was enhanced by 200μg/mL potassium sorbate. Lactic acid bacteria was toxic to C. sorokiniana cell at certain extent,cell density,chlorophyll content and Fv/Fm of C. sorokiniana decreased as the concentration increased. Adding 0.1-10.0 μg/mL dimethyl fumarate did not affect the cell density and chlorophyll content of C. sorokiniana,but the Fv/Fm significantly decreased.ConclusionIn establishing axenic culture of C. soroki-niana ,the suitable antibiotics are penicillin and cefotaxime sodium ,suitable preservative is potassium sorbate. The optimal concentration are 100μg/mL(penicillin),80μg/mL(cefotaxime sodium)and 200μg/mL(potassium sorbate) respectively.