Native polyculture microalgae is a promising scheme to produce microalgal biomass as biofuel feedstock in an open raceway pond. However, predicting biomass productivity of native polycultures microalgae is incredibly complicated. Therefore, developing polyculture growth model to forecast biomass yield is indispensable for commercial-scale production. This research aims to develop a polyculture growth model for native microalgal communities in the Minamisoma algae plant and to estimate biomass and biocrude oil productivity in a semicontinuous open raceway pond. The model was built based on monoculture growth of polyculture species and it is later formulated using species growth, polyculture factor (k_value), initial concentration, light intensity, and temperature. In order to calculate species growth, a simplified Monod model was applied. In the simulation, 115 samples of the 2014–2015 field dataset were used for model training, and 70 samples of the 2017 field dataset were used for model validation. The model simulation on biomass concentration showed that the polyculture growth model with k_value had a root-mean-square error of 0.12, whereas model validation provided a better result with a root-mean-square error of 0.08. Biomass productivity forecast showed maximum productivity of 18.87 g/m²/d in June with an annual average of 13.59 g/m²/d. Biocrude oil yield forecast indicated that hydrothermal liquefaction process was more suitable with a maximum productivity of 0.59 g/m²/d compared with solvent extraction which was only 0.19 g/m²/d. With satisfactory root-mean-square errors less than 0.3, this polyculture growth model can be applied to forecast the productivity of native microalgae.

中文翻译：

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一种用于估计生物燃料生产的生物质生产力的本地微藻群落的新型混养生长模型

天然混养微藻是在开放式水道池塘中生产微藻生物质作为生物燃料原料的有前途的方案。然而，预测本地混养微藻的生物质生产力非常复杂。因此，开发混养生长模型来预测生物量产量对于商业规模生产是必不可少的。本研究旨在为 Minamisoma 藻类植物中的本地微藻群落开发混养生长模型，并估计半连续开放式跑道池塘中的生物量和生物原油生产力。该模型是基于混养物种的单养生长建立的，后来根据物种生长、混养因子（k_值)、初始浓度、光强度和温度。为了计算物种生长，应用了简化的 Monod 模型。在模拟中，2014-2015年野外数据集的115个样本用于模型训练，2017年野外数据集的70个样本用于模型验证。生物量浓度的模型模拟表明，k_值的混养生长模型的均方根误差为0.12，而模型验证提供了更好的结果，均方根误差为0.08。生物质生产力预测显示，6 月份最高生产力为 18.87 g/m ² /d，年平均为 13.59 g/m ²/d。生物原油产量预测表明，水热液化工艺更适合，最大生产率为0.59 g/m ² /d，而溶剂萃取仅为0.19 g/m ² /d。令人满意的均方根误差小于 0.3，这种混养生长模型可用于预测本地微藻的生产力。