초록
<P><B>Abstract</B></P> <P>As one of the most promising renewable energy, microalgal biodiesel has been widely studied worldwide. However, the low-efficiency of conventional microalgae cultivation procedures restrict the development of microalgae biodiesel production. Microalgal-bacterial symbiosis could both enhance the growth of algal-bacterial culture and promote the removal and conversion of wastewater nutrients. In this study, three strains of high-efficient heterotrophic ammonia-oxidizing bacteria JN1, FN3, and FN5 were screened from municipal wastewater treatment system with over 80% degradation rates of 50 mg/L ammonia-nitrogen (NH<SUB>3</SUB>–N) in 24 h. Among them, FN5, belonging to <I>Kluyvera</I> sp., had the optimum effect on enhancing growth of oil-rich microalga <I>Chlorella pyrenoidosa</I>. In stationary phase, the biomass and lipid content of <I>Chlorella pyrenoidosa</I> was14.8% and 13.6% higher than the blank control tests without FN5. In contrast, JN1 and FN3 failed to enhance the growth of <I>Chlorella pyrenoidosa</I>. After the cultivation of <I>Chlorella pyrenoidosa</I>-FN5 consortia in municipal wastewater, the degradation rate of NH<SUB>3</SUB>–N was up to 91% while the content of microalgae biomass and lipid attained 0.35 g/L and 39.0%. The Saturated fatty acids (SFAs), Monounsaturated fatty acids (MUFAs), and Polyunsaturated fatty acids (PUFAs) were 43.9, 37.1 and 19.0%, respectively, which had the potential for biodiesel production after pretreatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High-efficient ammonia-oxidizing strain FN5 was identified and enriched. </LI> <LI> FN5 enhanced biomass concentration and lipid content of microalga <I>Chlorella pyrenoidosa.</I> </LI> <LI> <I>Chlorella pyrenoidosa-</I>FN5 culture removed NH3–N while accumulating higher microalgal lipid amounts. </LI> </UL> </P>