Abstract A colonial microalga, Botryococcus braunii synthesizes extracellular polysaccharides (EPS) forming a sheath around its colonies, which limits the extraction of hydrocarbons from this microalga. As thermal or mechanical pretreatment of B. braunii improves the hydrocarbon yield, the EPS removal and degree of algal colony disruption before and after pretreatment were evaluated using zeta potential and particle size distribution (PSD) to predict hydrocarbon yield from the alga. Since zeta potential can evaluate the ionizable state of particles, the zeta potential of B. braunii would be able to evaluate the removal degree of EPS and this feature had the potential to determine hydrocarbon yield quickly. The zeta potential of algal samples without pretreatment was −30.5 mV at pH 9, whereas that with pretreatment ranged from −29.7 to −18.8 mV. The elevation of zeta potential and EPS removal had a linear relationship (R-squared value = 0.96). The hydrocarbon yields exponentially increased in proportion to the degree of colony disruption after mechanical treatments (R-squared value = 0.81). These findings suggest that the zeta potential and PSD of B. braunii may be used as indicators for EPS removal and hydrocarbon yield.

中文翻译：

---

湿葡萄球菌产烃量的预测：菌落表面电荷和直径对可提取烃量的影响

摘要 Botryococcus braunii 是一种菌落微藻，它合成胞外多糖 (EPS)，在其菌落周围形成一个鞘，这限制了从这种微藻中提取碳氢化合物。由于 B. braunii 的热或机械预处理提高了碳氢化合物产量，因此使用 zeta 电位和粒度分布 (PSD) 评估预处理前后的 EPS 去除和藻类菌落破坏程度，以预测藻类的碳氢化合物产量。由于zeta 电位可以评价粒子的可电离状态，B. braunii 的zeta 电位可以评价EPS 的去除程度，该特征具有快速确定烃产率的潜力。未经预处理的藻类样品的 zeta 电位在 pH 9 时为 -30.5 mV，而经过预处理的则为 -29.7 至 -18.8 mV。zeta 电位的升高与 EPS 的去除呈线性关系（R 平方值 = 0.96）。碳氢化合物的产量与机械处理后菌落破坏的程度成正比（R 平方值 = 0.81）。这些发现表明 B. braunii 的 zeta 电位和 PSD 可用作 EPS 去除和碳氢化合物产量的指标。