ABSTRACT

Invading microorganisms can hinder productivity of biofuel algae cultures. We utilise allelochemical gramine as a model to better understand allelopathic effects against Chlorella sorokiniana and invasive alga Coelastrella sp. Coelastrella itself inhibits C. sorokiniana via allelopathy. Both algae were exposed to 0, 4, 8, 16, 32, 64 mg gramine L⁻¹ (n = 8) in wellplates at 18, 25 and 32°C to observe temperature effects on gramine’s allelopathic influence. We also grew C. sorokiniana in 500 mL flasks (n = 3) in 0, 4, 8 and 16 mg gramine L⁻¹ at 25°C to obtain enough biomass to measure fatty acid content. Growth was estimated by measuring optical density at 750 nm and fatty acid content of flask-grown algae via high-lipid performance chromatography (HLPC) after 30 days. Gramine impacted both algae species most strongly, even at low gramine dosages, when grown under sub-optimal temperatures (18 and 32°C). At 25°C, only the highest gramine concentration showed a significant reduction in C. sorokiniana growth compared to other treatments. Gramine concentrations above 16 mg L⁻¹ significantly impacted Coelastrella. Gramine effected algae growth over only a few days. Low concentrations of gramine (<16 mg L⁻¹) were not effective stressors to increase lipid accumulation.

摘要

入侵的微生物会阻碍生物燃料藻类培养物的生产力。我们利用化感化学禾本科植物作为模型，以更好地了解对小球藻和入侵藻类Coelastrella sp的化感作用。Coelastrella本身通过化感作用抑制了C. sorokiniana。将两种藻类分别 在18、25和32°C的孔板中分别暴露于0、4、8、16、32、64 mg氨水L ^-1（n = 8），以观察温度对氨水的化感作用的影响。我们还在0、4、8 和16 mg的氨水L ^-1中在500 mL烧瓶（n = 3）中生长了梭状芽胞杆菌。在25°C下获得足够的生物量以测量脂肪酸含量。30天后，通过高脂质性能色谱法（HLPC）通过测量750nm处的光密度和烧瓶中生长的藻类的脂肪酸含量来估计生长。当在次优温度（18和32°C）下生长时，即使在低剂量的禾本科植物中，禾本科植物对两种藻类的影响最大。与其他处理方法相比，在25°C下，只有最高的禾本科植物浓度才显示sorokiniana的生长显着降低。高于16 mg L ^-1的草胺浓度显着影响了腔肠蠕虫。禾本科仅在几天内就影响了藻类的生长。低浓度的禾胺（<16 mg L ^-1）不是增加脂质积累的有效压力源。