Table_1_A closer look into the microbiome of microalgal cultures.pdf

Although bacteria are commonly co-occurring in microalgal cultivation and production systems, little is known about their community structure and how it might be affected by specific microalgal groups or growth conditions. A better understanding about the underlying factors that determine the growth of specific bacterial populations is not only important for optimizing microalgal production processes, but also in the context of product quality when the algal biomass is to be used for future food or feed. We analyzed the bacterial community composition associated with nine microalgal strains in stock culture, maintained in two different growth media, to explore how specific taxonomic microalgal groups, microalgal origin, or the growth medium affect the bacterial community composition. Furthermore, we monitored the bacterial community composition for three Phaeodactylum strains during batch cultivation in bubble columns to examine if the bacterial composition alters during cultivation. Our results reveal that different microalgal genera, kept at the same cultivation conditions over many years, displayed separate and unique bacterial communities, and that different strains of the same genus had very similar bacterial community compositions, despite originating from different habitats. However, when maintained in a different growth medium, the bacterial composition changed for some. During batch cultivation, the bacterial community structure remained relatively stable for each Phaeodactylum strain. This indicates that microalgae seem to impact the development of the associated bacterial communities and that different microalgal genera could create distinct conditions that select for dominance of specific bacteria. However, other factors such as the composition of growth medium also affect the formation of the bacterial community structure.

尽管细菌普遍共存于微藻（microalgae）培养与生产体系中，但学界对其群落结构，以及特定微藻类群或生长条件如何影响该群落的机制仍知之甚少。深入解析调控特定细菌种群生长的潜在影响因素，不仅对优化微藻生产工艺具有重要意义，同时在藻生物质未来用作食品或饲料原料时，也对保障产品品质至关重要。本研究针对保藏于两种不同培养基中的9株原种培养微藻菌株的附生细菌群落组成展开分析，以探究特定分类学微藻类群、微藻来源及培养基组成如何影响细菌群落结构。此外，本研究在鼓泡柱（bubble columns）分批培养（batch cultivation）体系中，对3株三角褐指藻（Phaeodactylum）的细菌群落组成进行动态监测，以考察培养过程中细菌群落组成是否发生改变。研究结果显示，尽管多年来在相同培养条件下保藏，不同微藻属仍各自拥有独特的附生细菌群落；而同一属内的不同菌株，即便来源生境不同，其细菌群落组成也极为相似。但部分微藻菌株在更换培养基类型后，其附生细菌群落组成会发生改变。在分批培养过程中，各三角褐指藻菌株的细菌群落结构均保持相对稳定。这表明微藻可对其附生细菌群落的构建产生影响，不同微藻属能够营造差异化的生境条件，从而筛选出特定优势细菌类群；但培养基组成等其他因素同样会对细菌群落结构的形成产生调控作用。