Tripathi Serveshwar Dutt, Mitra Romit, Kulshrestha Samridhi, Rabiya Rabiya, Sen Ramkrishna
Department of Bioscience & Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur - 721302, Paschim Medinipur, West Bengal, India.
P K Sinha Centre for Bioenergy & Renewables, Indian Institute of Technology Kharagpur, Kharagpur - 721302, Paschim Medinipur, West Bengal, India.
Bioresour Technol. 2025 May;423:132232. doi: 10.1016/j.biortech.2025.132232. Epub 2025 Feb 15.
Chlorella vulgaris, a green microalga, produces extracellular polymeric substances (EPSs) that aid in microalgal self-settling and offer protection against physicochemical stresses. To develop an efficient bioprocess for EPS production, C. vulgaris was cultivated in modified Bold's Basal Medium with varying initial concentrations of sodium bicarbonate in photobioreactors. At 130 mM bicarbonate, higher biomass concentration of 1.60 ± 0.04 g/L and productivity of 0.19 ± 0.02 g/L/d were achieved after 8 days. A relatively higher EPS yield of 183 ± 2 mg/g biomass was obtained at 190 mM bicarbonate resulting in 5-fold increase over control. EPS promoted maximum microalgal auto-flocculation within 8 h in 190 mM bicarbonate and was identified as a glycoprotein with molecular weight of 1400 kDa. This innovative strategy of utilizing bicarbonate as a source of dissolved inorganic carbon not only enhances EPS production but also demonstrates a potentially scalable method for carbon dioxide capture from flue gases.
小球藻是一种绿色微藻，能产生胞外聚合物（EPSs），有助于微藻自我沉降，并提供抵御物理化学胁迫的保护作用。为开发一种高效的EPS生产生物工艺，在光生物反应器中，用初始浓度不同的碳酸氢钠改良Bold基础培养基培养小球藻。在130 mM碳酸氢钠条件下，8天后实现了较高的生物量浓度，为1.60±0.04 g/L，生产力为0.19±0.02 g/L/天。在190 mM碳酸氢钠条件下，获得了相对较高的EPS产量，为183±2 mg/g生物量，比对照提高了5倍。在190 mM碳酸氢钠中，EPS在8小时内促进了最大程度的微藻自动絮凝，并且被鉴定为分子量为1400 kDa的糖蛋白。这种利用碳酸氢盐作为溶解无机碳源的创新策略不仅提高了EPS产量，还展示了一种从烟道气中捕获二氧化碳的潜在可扩展方法。
