Eukaryotic microalgae and prokaryotic cyanobacteria can grow in various water and wastewater types, and both can grow biomass by taking nutrients and converting atmospheric CO₂ into useful products. Biofuels obtained by processing this landless grown biomass are defined as “third-generation biofuels”. In this study, the effects of hydrodynamic cavitation (HC)-assisted NaOH pretreatment on methane production from cyanobacteria were investigated. Cyanobacterial biomass was isolated from thermal springs located in the southwest of Turkey (Denizli-Turkey) and identified as Desertifilum tharense. Desertifilum tharense biomass was grown on a laboratory scale, and along with its compositional characteristics, culture-specific parameters were determined. HC-assisted NaOH pretreatment was applied to evaluate optimum process conditions for enhancing methane production from D. tharense. In the experimental design, process parameters of cavitation number (Cv: 0.3-0.7), NaOH concentration (0–4%), solid content (1.5%), reaction time (4h), and reaction temperature (30°C) were combined to reveal the parameter-specific impact of HC pretreatment. The effect of the HC-assisted NaOH pretreatment was further investigated with molecular-bond and surface structure characterization. Along with the energy equivalent of obtained biofuel, energy requirements for cultivation, harvesting, pretreatment, and anaerobic digestion (AD) were calculated to determine the process’s overall energy efficiency. Kinetic parameters of raw and pretreated D. tharense were determined by first-order, cone, modified Gompertz, and reaction curve models. The results revealed that by the application of pretreatment, a 2-35.3% soluble COD increase was achieved, whereas methane production was increased from 241.5 to 290.6 mLCH₄ gVS⁻¹. Application of HC with a low Cv of 0.3 boosted methane production up to 20.3% compared to the raw D. tharense.

真核微藻类和原核蓝细菌可以在各种水和废水中生长，并且都可以通过吸收营养并将大气中的CO ₂转化为有用的产品来生长生物质。通过处理这种无土地种植的生物质而获得的生物燃料被定义为“第三代生物燃料”。在这项研究中，研究了水力空化（HC）辅助的NaOH预处理对蓝细菌产生甲烷的影响。蓝藻生物质是从位于土耳其西南部（Denizli-Turkey）的温泉中分离出来的，被鉴定为塔勒菲沙漠。沙漠荒漠生物量以实验室规模生长，并与其组成特征一起确定了培养物特异性参数。HC辅助的NaOH预处理用于评估最佳工艺条件以提高D. tharense甲烷的产量。在实验设计中，空化数的工艺参数（Cv：0.3-0.7），NaOH浓度（0–4％），固含量（1.5％），反应时间（4h）和反应温度（30°C）相结合，揭示了HC预处理对参数特定的影响。通过分子键和表面结构表征进一步研究了HC辅助NaOH预处理的效果。除了获得的生物燃料的能量当量外，还计算了种植，收获，预处理和厌氧消化（AD）的能量需求，以确定过程的整体能量效率。原始和预处理的D. tharense的动力学参数由一阶，圆锥，修正的Gompertz和反应曲线模型确定。结果表明，通过预处理的应用，可溶COD增加了2-35.3％，而甲烷产量从241.5增加到290.6 mLCH ₄ gVS ^-1。与原始D. tharense相比，低Cv为0.3的HC的应用将甲烷产量提高了20.3％。