Nham Quyen, Gordon Tristan, Farnelid Hanna, Legrand Catherine, Lindehoff Elin
Department of Biology and Environmental Science, Linnaeus University Centre for Ecology and Evolution in Microbial model Systems, Linnaeus University, Kalmar, Sweden.
School of Health and Welfare, Jönköping University, Jönköping, Sweden.
Biotechnol Bioeng. 2025 Oct;122(10):2688-2700. doi: 10.1002/bit.70027. Epub 2025 Jul 18.
In algal cultivation, nighttime biomass loss due to respiration and cell mortality can considerably reduce the amount of biomass produced during daylight. The adverse effect can be counteracted by mixotrophic cultivation, where an organic carbon (OC) source is used to supply the energy required for cell maintenance and division during darkness. The potential for mixotrophic cultivation to mitigate night biomass loss has yet to be tested under outdoor, large-scale conditions that use raw industrial waste streams, particularly during low-light seasons. We investigated night biomass loss in cultivation of the strain Monoraphidium minutum KAC90 in outdoor 1 m raceway ponds during the Nordic autumn. Flue gas condensate (nitrogen source) and cheese whey (phosphorus and OC source) were used for the mixotrophic treatment, while potassium monophosphate (phosphorus source) was used for the photoautotrophic control. Results indicate that under high OC availability, the mixotrophic treatment had a night biomass gain of 33% ± 16%, whereas it experienced a night biomass loss of 10% ± 9% under low OC. In contrast, the photoautotrophic control showed a night biomass loss of 5% ± 15%. In the mixotrophic treatment, algal biomass had a higher carbohydrate content, but lower levels of lipids and proteins than the photoautotrophic cultures. The cultivation of algae using cheese whey may increase biomass accumulation in darkness, enhancing the overall production of algal biomass rich in carbohydrates.
在藻类培养中，由于呼吸作用和细胞死亡导致的夜间生物量损失会显著减少白天产生的生物量。这种不利影响可以通过混合营养培养来抵消，即在黑暗期间使用有机碳（OC）源来提供细胞维持和分裂所需的能量。在使用原始工业废物流的室外大规模条件下，尤其是在低光照季节，混合营养培养减轻夜间生物量损失的潜力尚未得到测试。我们研究了北欧秋季期间，在室外1米跑道池塘中培养微小单歧藻KAC90菌株时的夜间生物量损失情况。混合营养处理使用烟道气冷凝液（氮源）和奶酪乳清（磷和OC源），而光自养对照使用磷酸二氢钾（磷源）。结果表明，在高OC可用性下，混合营养处理的夜间生物量增加了33%±16%，而在低OC条件下夜间生物量损失了10%±9%。相比之下，光自养对照的夜间生物量损失为5%±15%。在混合营养处理中，藻类生物量的碳水化合物含量较高，但脂质和蛋白质水平低于光自养培养物。使用奶酪乳清培养藻类可能会增加黑暗中的生物量积累，提高富含碳水化合物的藻类生物量的总体产量。
