STUDY ON THE EFFECTS OF DIFFERENT NUTRITION MODES ON THE GROWTH OF CHLORELLA SP. FACHB 484 AND THE MECHANISM OF HETEROTROPHIC GROWTH

Here we systematically studied the growth of Chlorella sp. FACHB 484 in glucose-containing medium in different nutrition modes. We also conducted the inhibition tests to investigate the effects of glucose on the growth of Chlorella sp. FACHB 484 in heterotrophic and mixotrophic conditions, as well as to identify the key enzyme in oxidation respiratory system. We observed that Chlorella sp. FACHB 484 could utilize glucose as the source of nutrition in all the test nutritional modes and showed different growth rates in the order mixotrophy photoheterotrophy light-activated heterotrophy chemoheterotrophy photoautotrophy. The maximum biomass and specific growth rate (SGR) of the tested algae in mixotrophy were 8.6 and 3.4 times higher than those in photoautotrophy. The value of SGR of Chlorella sp. FACHB 484 in mixotrophy was close to the sum of the values of SGRs in photoautotrophy and photoheterotrophy. In mixotrophic and photoheterotrophic modes, Chlorella sp. FACHB 484 used glucose and light as the sources of carbon and energy respectively. The cells of Chlorella sp. FACHB 484 expresses succinic dehydrogenase and cytochrome oxidase which are most likely the key enzymes of the oxidation respiratory chain.