This study evaluated the feasibility of using effluent from the anodic chamber of a microbial fuel cell (MFC), powered by real fruit and vegetable wastewater, as a cultivation medium for Tetraselmis subcordiformis, a microalga capable of bio-photolytic hydrogen production. In three experimental variants, different organic loading rates were applied in the anodic chamber, resulting in significant differences in effluent quality and its suitability as a culture medium. In contrast to the dominant MFC configurations, in which microalgae act as cathodic biocatalysts, the microbial fuel cell in this study was used as a source of the inevitable anode effluent, which was subsequently valorized as a cultivation medium for the marine microalga T. subcordiformis to support biomass and hydrogen production. In variants with moderate COD concentration and low lipid content, the highest biomass concentrations, ranging from 941 ± 104 mg VS/L to 1020 ± 108 mg VS/L, were obtained, along with the highest nitrogen assimilation efficiency (48.7–49.1%) and phosphorus assimilation efficiency (62.3–63.1%). The variant in which the culture medium contained the highest concentrations of COD, TSS, and lipids showed a substantial limitation of biomass growth to 745 ± 75 mg VS/L and lower nutrient removal efficiency (total nitrogen—42.3 ± 4.7%, total phosphorus—55.0 ± 5.0%). The obtained biomass was then used for H2 production in a mineral photobiolytic medium. The highest total hydrogen production reached 184.7 ± 25.0 mL, while the specific hydrogen yield reached 193.7 ± 32.6 mL/g VS. Increased concentration of organic matter in the medium reduced total hydrogen production to 112.0 ± 14.8 mL, mainly due to lower biomass concentration, although the specific hydrogen yield remained high (153.4 ± 25.8 mL/g VS). The biogas composition was stable (H2 58.0–58.7%, CO2 35.3–35.9%, O2 6.0–6.2%).

The regulations in force in the European Union require the thermal pre-treatment of substrates containing animal by-products prior to the anaerobic digestion (AD) process. Expired food products (EFP) belong to this category of substrates. Traditionally, the requirement for thermal pre-treatment has been met with waste heat from combined heat and power plants (CHP). However, due to the increasing trend towards biomethane production and the move away from CHP, alternative heating methods need to be explored. The main objective of this study was to evaluate the impact of the dual synergistic effect achieved by ultrasonic-thermal pre-treatment of EFP on the kinetics, efficiency and energy balance of AD. The combined thermal treatment and ultrasonic disintegration at 90 degrees C resulted in an increase in dissolved phase chemical oxygen demand (COD) by (84.4 +/- 3.9) % and total organic carbon (TOC) by (56.8 +/- 6.2) %, leading to final concentrations of (33010 +/- 1280) mg O-2/L and (10710 +/- 670) mg Corg/L, respectively. After thermal pretreatment of EFP at 70 degrees C, the methane yield reached (515 +/- 24) mL/g VS, while at 90 degrees C it increased to (525 +/- 22) mL/g VS. The application of ultrasonic thermal pretreatment resulted in a positive net energy gain, with the most efficient variant yielding (4.20 +/- 0.23) Wh, which was (0.37 +/- 0.17) Wh higher than the control sample. In contrast, a negative energy balance was observed in the variants where conventional heating methods were used.

The efficiency of anaerobic digestion (AD) of lignocellulosic biomass is strongly determined by biomass yield, chemical composition, and bioavailability, all of which undergo substantial seasonal variation. However, integrated analyses linking these factors with AD performance, process kinetics, and energy-economic efficiency remain limited. This study aimed to evaluate the effect of seasonal variability in the chemical composition of Helianthus annuus biomass on AD efficiency from a technological and economic perspective. The novelty of this study lies in integrating seasonal changes in biomass composition with AD kinetics, CH4 productivity per hectare, and CHP techno-economic performance to identify the optimal harvest window for Helianthus annuus. The experiments were conducted using biomass harvested from June to December. The results showed significant (p < 0.05) variability in biomass properties, including a progressive increase in lignocellulosic fractions over the growing season, with neutral detergent fiber (NDF) increasing from 30.58 +/- 1.8 to 66.58 +/- 3.1% TS and acid detergent lignin (ADL) from 5.13 +/- 0.5 to 10.35 +/- 0.9% TS, accompanied by a decline in substrate bioavailability. The maximum CH4 yield of 258 +/- 13 mL/g VS was obtained in August, with a process rate of 29.0 +/- 3.4 mL/g VS & centerdot;d and the highest utilization of methane potential, reaching 62.5 +/- 3.8% (BMPCH4/TBMP). Correlation and regression analyses indicated that ADL and NDF were the strongest empirical predictors of AD performance within the analyzed dataset, showing a negative association with both CH4 production yield and kinetics (R-2 up to 0.86), whereas reducing sugars had a stimulatory effect. Multiple regression models showed high predictive performance, with R-2 = 0.889 for BMPCH4. The highest energy and economic efficiency was achieved in summer. In August, CH4 production reached 3214 +/- 596 m(3)/ha, corresponding to 11.2 +/- 2.1 MWh/ha of electricity and a net result of 1559 +/- 417 EUR/ha. Increased lignification in the later part of the season led to reduced process efficiency and a deterioration of the economic balance. From a practical perspective, these results demonstrate that harvest scheduling should be based on the trade-off between biomass quantity and biodegradability rather than on biomass yield alone.

The objective of this study was to evaluate the impact of seasonal changes in the chemical and structural composition of giant miscanthus (Miscanthus & times; giganteus) biomass on the performance, kinetics, and efficiency of anaerobic digestion (AD), as well as on the overall energy and techno-economic balance of the conversion chain. The AD performance was assessed using batch biochemical methane potential (BMP) assays conducted for eight harvest dates (June-January). Comprehensive characterization included fundamental physicochemical properties of the biomass, lignocellulosic fraction composition, AD kinetics, and methane production yield. A statistically significant (p < 0.05) increase in structural fiber fractions was observed with advancing plant maturity, accompanied by a progressive decline in specific methane yield from 281 +/- 32 mL CH4/g VS in June to 170 +/- 11-172 +/- 13 mL CH4/g VS in winter harvests. Despite a relatively stable theoretical biochemical methane potential (TBMP) ranging from 425 to 443 mL CH4/g VS, the conversion efficiency (BMP/TBMP) decreased from approximately 66% to below 40%, indicating increasing structural and kinetic limitations to substrate biodegradability. Kinetic parameters deteriorated systematically in late harvests, as reflected by a reduction in the first-order rate constant k_CH4 from 0.115 to approximately 0.072 1/d and an extension of the lag phase lambda from 2.19 to over 4 days. Regression analysis revealed strong negative correlations between lignocellulosic complex content and both BMP and k_CH4, whereas the C/N ratio exhibited a positive association with process performance under the experimental conditions applied. The highest methane production per hectare (3904 +/- 720 m(3)CH(4)/ha) and the most favorable economic outcome (1979 +/- 465 EUR/ha) were achieved for the September harvest. The results demonstrate that harvest timing constitutes a critical optimization parameter in lignocellulosic biogas systems, governing not only methane yield and process kinetics but also the overall energy output and economic viability of the bioenergy production chain.

Microalgae and cyanobacteria represent promising, sustainable resources for agricultural applications, particularly as biofertilisers, biostimulants, and biological plant protection agents. Their biomass can improve nutrient use efficiency, support plant growth and yield, and enhance soil structure and microbial activity, while cyanobacteria additionally contribute through biological nitrogen fixation, reducing reliance on synthetic fertilisers. The integration of microalgal cultivation with closed-loop systems, such as wastewater treatment plants or biogas facilities, enables nutrient recovery, production of value-added biomass, and mitigation of greenhouse gas emissions. This review synthesises current knowledge on the biochemical composition, functional properties, and mechanisms of action of microalgal and cyanobacterial biomass in relation to these established agricultural applications. In addition, prevailing research trends, selected technological and organisational constraints, and implementation challenges are discussed. Particular attention is given to emerging application contexts, including bioregenerative life support systems (BLSS) for space agriculture, where microalgae and cyanobacteria can contribute to oxygen production, nutrient recycling, and edible biomass generation. Species such as Chlorella vulgaris, Arthrospira platensis, and Scenedesmus obliquus demonstrate tolerance to microgravity, radiation, and limited light conditions, supporting their potential use in closed, self-sufficient cultivation systems. Although numerous reviews have addressed individual agricultural applications of microalgae and cyanobacteria, a more integrative perspective that connects biological functionality with broader technological, regulatory, and implementation contexts remains valuable. The present review contributes to this perspective by consolidating established agronomic uses and extending the discussion toward selected emerging applications, thereby providing a structured framework for future research and development in sustainable terrestrial and extraterrestrial agriculture.

The aim of this study was to evaluate the effect of Sida hermaphrodita harvest timing on biomass composition, properties, and methane fermentation performance. In addition, an energy–economic assessment was performed for biomass obtained at different stages of the growing season. The economic assessment assumed CHP electrical and thermal efficiencies of 38% and 47%, electricity and heat prices of 0.18 and 0.05 EUR/kWh, respectively, month-specific agrotechnical costs, and OPEX equal to 30% of total energy revenue. The biomass exhibited clear seasonal changes, transitioning from a material with high bioavailability during the summer period to a structurally more recalcitrant substrate in the autumn and winter months, as indicated by increasing lignification and fibrous fraction contents. The highest CH4 production yields, ranging from 300 to 320 mL/g VS, and maximum production rates of up to 33.5 mL/g VS·d were obtained between June and August. In December, the CH4 yield decreased to 180 ± 9 mL/g VS, accompanied by a substantial deterioration in kinetic performance. Despite the relatively stable theoretical methane potential, which ranged from 405 to 430 mL/g VS, its conversion efficiency declined from 77.1% in the summer period to 41.9% in the winter period. Regression analysis confirmed the key influence of the C/N ratio and total solids content, with model fits reaching R2 values of 0.74–0.80, while the structure of lignocellulosic complexes had a less pronounced but still relevant effect. The maximum CH4 production per unit cultivation area, approaching 3380 m3/ha, was achieved in July–August, reflecting a balance between high specific methane yield and biomass productivity. At the same time, the results demonstrated that the maximum biomass yield did not translate into the highest energy and economic performance. The highest net economic return, 1789 ± 330 EUR/ha, was obtained in July, despite biomass yield being 13.6% higher in September. These findings indicate a seasonal decoupling between biomass yield and energy performance, highlight biomass quality as a critical determinant of anaerobic digestion efficiency, and support harvest-date optimization as a low-cost strategy for the practical use of S. hermaphrodita in agricultural biogas plants. Further long-term continuous and semi-continuous studies are required to validate process stability and performance under industrial operating conditions.

Increasing demands for improved energy efficiency and resource recovery in wastewater management have driven intensified research on microalgal–bacterial consortia (M-BC). This technological approach represents one of the most promising and continuously evolving concepts for integrated wastewater treatment and energy recovery. M-BC systems exploit complementary processes, including photosynthesis, oxygen production, nutrient uptake by microalgae, as well as heterotrophic degradation of organic contaminants and CO2 generation by bacteria. Laboratory- and pilot-scale studies demonstrate that such integration can substantially reduce energy demand while significantly improving technological performance. Metabolic synergy, metabolite exchange, intercellular communication, and the specific aggregate architecture collectively determine the stability and high productivity of these consortia. Depending on operational conditions, M-BC may occur as suspended cultures, biofilm-based systems, or granules, which differ in process characteristics and biomass recovery potential. Available evidence indicates that M-BC biomass can serve as a highly efficient substrate for anaerobic digestion (AD). The methane production potential of M-BC reaches 350–365 mL CH4/gVS, and following pretreatment may increase to 530–560 mL CH4/gVS, exceeding typical ranges reported for conventional sewage sludge. These values were obtained under specific process conditions and depend on biomass characteristics, consortium structure, inoculum type, and operational parameters; therefore, their generalisation should be interpreted with caution. However, practical implementation remains constrained by process-related barriers directly affecting AD performance, including extracellular polymeric substance (EPS)-mediated hydrolysis limitation and nitrogen-associated inhibition linked to low C/N ratios and ammonia accumulation. Additional challenges include seasonal variability in biomass composition and incomplete understanding of M-BC behaviour under anaerobic conditions, particularly at scale. This paper provides a comprehensive and integrative analysis of the structure and biochemistry of M-BC biomass, their ecological mechanisms, technological configurations, and current knowledge regarding their susceptibility to anaerobic digestion. The review identifies the key biological, chemical, and process-related barriers and highlights research directions required for future integration of M-BC into circular wastewater treatment systems and energy-oriented biomass valorisation.

The sustainable and economically viable production of microalgae biomass for biofuels and high-value bioproducts is highly dependent on precise, multi-parametric monitoring of cultivation systems. This review provides a comprehensive overview of current approaches and technological advances in multi-sensor systems applied to photobioreactors, including flow cytometry, IR spectroscopy, RGB sensors, in situ microscopy, and software-based sensors. The integration of artificial intelligence (AI), the Internet of Things (IoT) and metaheuristic algorithms into monitoring systems is also discussed as a promising way to optimise key ecological, physicochemical, and biological parameters in real time. The report highlights critical factors that influence biomass growth and product yield, such as nutrient concentrations, light intensity, CO2 levels, pH and temperature. In addition, current technological limitations are highlighted, and future strategies for improving monitoring accuracy, automating cultivation, and improving the biosynthesis of metabolites are outlined. Through a synthesis of the literature and technological trends, this work contributes to the development of smart photobioreactor systems and provides actionable insights to improve large-scale, highly efficient microalgae cultivation in energy and environmental biotechnology.

Long-term anaerobic co-digestion of lignocellulosic biomass Sida hermaphrodita and cattle manure was investigated under different organic loading rates (OLRs) (S1 – 2 kgVS/(m3·d), S2 – 3 kgVS/(m3·d), S3 – 4 kgVS/(m3·d)). The study examined the methane production, microbial community, and volatile fatty acids (VFAs). During the S1 and S2, the methane production was stable, and it reached 446.3±153.7 NL/kgVS and 773.4±107.8 NL/kgVS, respectively. In the S3, the methane production was reduced, the pH dropped from 7.68 to 6.11, the FOS/TAC ratio increased from 0.272 to 0.35, and the accumulation of acetic and propionic acid at the end of digester cycle was observed. The abundance of Firmicutes increased with increasing the OLR in the digester (reached 93.6% in the S3), while Bacteroidota abundance decreased with increasing the OLR in the digester (reached 3.0% in the S3). In the S1, the methane was produced through the acetoclastic and hydrogenotrophic pathways.

Microalgae microbial fuel cells (pMFCs) are distinguished by their ability to combine waste utilization with the simultaneous recovery of energy and valuable materials. The generation of high current density is linked to the efficient electron transfer to the anode via the anodic biofilm and the high photosynthetic activity of the microalgae cultivated in the cathode chamber. This review explores the impact of wastewater type on energy production and wastewater treatment. Additionally, it discusses the challenges related to microalgae growth in the cathode chamber, the necessity of aeration, and the sequestration of carbon dioxide from the anode chamber. The efficiency of microalgae in utilizing nutrients from various types of wastewater is also presented. In conclusion, the comparison between wastewater treatment and energy balance in pMFCs and conventional wastewater treatment plants is provided. On average, MFCs consume only 0.024 kW or 0.076 kWh/kg COD, which is approximately ten times less than the energy used by activated sludge bioprocesses. This demonstrates that MFCs offer highly efficient energy consumption compared to traditional wastewater treatment systems while simultaneously recovering energy through exoelectrogenic, bioelectrochemical processes.

In the face of accelerating climate change, increasing urbanisation and the progressive depletion of non-renewable energy and raw material resources, there is growing pressure worldwide to develop innovative, low-emission technologies for the recovery and processing of biowaste [...]

Biohydrogen is considered to be one of the fuels of the future, so there is a justified need to find efficient and cost-effective technologies for its production. This study evaluated the efficiency of two biohydrogen production pathways, specifically biophotolysis and dark fermentation, using Tetraselmis subcordiformis biomass. Microalgae production was performed in three variants, where the separation criterion was the type of culture medium: a control sample (synthetic medium; V1–PCR), agricultural wastewater from hydroponic tomato cultivation (V2–SL-WW), and effluent from a microbial fuel cell (V3–MFC-WW). The highest increase in biomass of T. subcordiformis was obtained in V2–SL-WW—2730 ± 212 mg VS/L, which was also associated with the maximum chlorophyll a content (65.0 ± 5.1 mg Chl-a/L). In biophotolysis, the highest specific hydrogen yields were obtained in V1–PCR (55.3 ± 4.3 mL/g VS) and V2 (54.3 ± 3.7 mL/g VS). The total hydrogen production in these variants was 166 ± 13 mL (V1–PCR) and 163 ± 11 mL (V2–SL-WW), respectively. The average H2 production rate reached 4.70 ± 0.33 mL/h in V2–SL-WW, and the rate constant (k) was 0.030–0.031 h−1. In anaerobic fermentation, the highest total and specific H2 production was obtained in V1–PCR, 453 ± 31 mL and 45.3 ± 3.1 mL/g VS, respectively. The qualitative composition of the biogas confirmed a high hydrogen content: 61.4% (biophotolysis, V1) and 41.1% (dark fermentation, V2–SL-WW). The results obtained confirm that T. subcordiformis can be effectively cultivated on waste media and that the biohydrogen production maintains a high technological efficiency through both photolytic and fermentative mechanisms. The medium from hydroponic tomato cultivation (V2–SL-WW) proved to be particularly promising, as it combines high biomass productivity with a satisfactory biohydrogen production profile.

The aim of this study was to evaluate the effect of low-temperature disintegration of Chlorella vulgaris using solidified carbon dioxide (SCO2) on the efficiency of anaerobic digestion of microalgae biomass. The novelty of this study resides in the pioneering application of SCO2 for the pretreatment of C. vulgaris biomass to enhance methane fermentation. This approach integrates mechanical disruption of cell walls with improved solubilization of organic fractions at low temperatures, providing an innovative and energy-efficient strategy to boost biomethanogenesis performance. This study was carried out in four stages, including characterisation of substrate properties, evaluation of organic compound solubilization following SCO2 pretreatment, and fermentation under both batch and continuous conditions. Analysis of dissolved COD and TOC fractions revealed a significant increase in the bioavailability of organic matter as a result of SCO2 application, with the highest degree of solubilization observed at a SCO2/C. vulgaris biomass volume ratio of 1:3. In batch reactors, CH4 yield increased significantly to 369 ± 16 mL CH4/g VS, methane content in biogas reached 65.9 ± 1.0%, and kinetic process parameters were improved. Comparable enhancements were observed in continuous fermentation, with the best scenario yielding 243.4 ± 9.5 mL CH4/g VS. Digestate analysis confirmed more efficient degradation of organic fractions, and the stability of methanogenic consortia was maintained, with only moderate changes in the relative abundance of the main groups (Methanosarcinaceae, Methanosaeta). Energy balance calculations indicated a positive net effect of the process. This study represents a pioneering application of SCO2 pretreatment in the context of microalgal biomass and highlights its high potential for intensifying anaerobic digestion.

This study analyzed the effects of thermohydrolysis on the anaerobic conversion efficiency of lignocellulosic biomass, comparing conventional and microwave heating methods. The research aimed to identify the optimal temperature and duration for biomass pre-treatment to maximize biogas output. Four temperatures (100 °C, 130 °C, 150 °C, and 180 °C) and six durations (10, 15, 20, 25, 30, and 40 min) were tested. The results showed that microwave heating increased biogas production compared to conventional heating at the same temperatures and durations. At 150 °C, microwave heating for 20 min produced 1184 ± 18 NmL/gVS of biogas, which was 16% more than the 1024 ± 25 NmL/gVS achieved through conventional heating. Statistically significant differences in biogas output between microwave and conventional heating were observed at 130 °C, 150 °C, and 180 °C, with the greatest difference recorded between 130 °C and 150 °C: 13% for conventional heating and 18% for microwave heating. Notably, increasing the temperature from 150 °C to 180 °C did not result in a statistically significant rise in biogas production. The energy balance analysis revealed that microwave heating, despite its lower efficiency compared to conventional heating, resulted in higher net energy gains. The most favorable energy balance for microwave heating was observed at 150 °C, with a net gain of 170.8 Wh/kg, while conventional heating at the same temperature achieved a gain of 126.2 Wh/kg. Microwave heating became cost-effective starting from 130 °C, yielding an energy surplus of 18.2 Wh/kg. The maximum energy output from microwave conditioning was 426 Wh/kg at 150 °C, which was 158 Wh/kg higher than conventional heating. These findings suggest that microwave thermohydrolysis, particularly at 150 °C for 20 min, enhances both biogas production and energy efficiency compared to conventional methods. The results highlight the potential of microwave pre-treatment as an effective strategy to boost methane fermentation yields, especially at temperatures above 130 °C.

Carbon dioxide (CO2) is often a limiting factor for the growth of microalgal biomass. Consequently, the search for new CO2 sources that do not contain components inhibitory to microalgal metabolism remains a priority. An alternative to the solutions tested thus far may involve the use of CO2-rich gas derived from microbial fuel cells (MFCs). This concept served as the basis for the original experimental work described in this study. The objective of the research was to evaluate the effect of using gases from the anode chamber of an MFC as a CO2 source in the autotrophic cultivation of Tetraselmis subcordiformis. The highest biomass growth efficiency was observed when the CO2 concentration in the culture medium was maintained at 220.0 ± 8.0 mg/L. Under these conditions, the microalga proliferation rate reached 0.52 ± 0.03 g VS/(L∙day) and 11.54 ± 0.42 mg chl-a/(L∙day), with a final biomass concentration of 2.68 ± 0.10 g VS/L and 63.53 ± 2.44 mg chl-a/L at the end of the cultivation cycle. Moreover, the highest total hydrogen (H2) production of 312 ± 38 mL was achieved in the same experimental variant, corresponding to an H2 production rate of 62.4 ± 6.1 mL/day. The removal efficiency of ammonium nitrogen (N-NH4) was notably high in experimental variants using MFC-derived biogas, ranging from 97.0 ± 2.2% to 98.2 ± 1.8%. Additionally, the growing microalgal biomass effectively utilized phosphate phosphorus (P-PO4) and iron, further highlighting its potential for nutrient recovery.

The organic loading rate (OLR) is a crucial parameter in the anaerobic digestion of lignocellulosic biomass. Optimizing the OLR ensures a balanced substrate release for gradual hydrolysis, thereby preventing the accumulation of inhibitors that can disrupt methanogenesis. Its significance lies in its direct impact on the stability, efficiency, and overall performance of the digestion process. This study investigated the long-term anaerobic co-digestion of lignocellulosic biomass (Sida hermaphrodita) and cattle manure under varying organic loading rates (S1: 2 kgVS/m3·d, S2: 3 kgVS/m3·d, and S3: 4 kgVS/m3·d). Methane production, microbial community dynamics, and volatile fatty acid (VFA) profiles were analyzed. During S1 and S2, methane production was stable, achieving 446.3 ± 153.7 NL/kgVS and 773.4 ± 107.8 NL/kgVS, respectively. However, at S3, methane production declined, accompanied by a pH drop from 7.68 to 6.11, an increase in the FOS/TAC ratio from 0.272 to 0.35, and the accumulation of acetic and propionic acids at the end of the digestion cycle. Microbial analysis revealed that the abundance of Firmicutes increased with higher OLRs, reaching 93.6% in S3, while the Bacteroidota abundance decreased, reaching 3.0% in S3. During S1, methane production occurred through both acetoclastic and hydrogenotrophic pathways.

The aim of the study was to evaluate the feasibility of using exhaust gases as a CO2 source in the cultivation of Tetraselmis subcordiformis microalgae for biomass and hydrogen production. It was shown that the growth rate of T. subcordiformis biomass and its biochemical composition depended on the CO2 source. The highest growth rate of 286 ± 15 mgVS/L-d and a final biomass concentration of 2710 ± 180 mgVS/L were achieved in the variant where exhaust gases from a coal and biomass supplementary combustion plant were the CO2 source (V2). The highest CO2 reduction efficiency of 90.3 ± 3.2% was achieved in the case where waste gases from biogas combustion were the CO2 source (V1). In V2, the highest CO2 utilization efficiency was achieved (CO2UE = 46.7 ± 2.4%). Analyzing the biomass composition confirmed differences in total carbon content (TC) and polysaccharide fraction. The highest H2 production efficiency and rate, which were 70.9 ± 2.7 mL/gVS and 2.27 ± 0.08 mL/gVS·h, respectively, were obtained in V2. The results obtained indicate the possibility of integrating fuel combustion processes with the cultivation of T. subcordiformis and photobiological H2 production, which is a promising solution in the context of climate neutrality and the implementation of circular economy postulates. This approach demonstrates a sustainable strategy for linking industrial CO2 emissions with the production of renewable biohydrogen and thus contributes to climate protection and the promotion of circular economy concepts.

This study assessed the potential of Chlorella vulgaris to biosequester carbon dioxide (CO2) and produce microalgal biomass using real exhaust gases from a municipal heating plant. Experiments were conducted in vertical tubular photobioreactors (V-PBRs) in three series: a control with atmospheric air as the CO2 source (S1), exhaust gases containing SOx (S2), and fully desulphurised exhaust gases (S3). The highest productivity of C. vulgaris was recorded in S3, where 2120 ± 123 mg VS/L was achieved with an exponential growth rate of 281.0 ± 16.2 mg VS/L·d. The presence of SOx in the gases caused the culture to die off as early as day 8 of the cultivation cycle, resulting in a decrease in biomass concentration and acidification of the culture medium. In S2, compared to the other experimental series, significantly lower organic carbon, lipid, and sugar contents were also observed in the microalgal biomass. However, protein content remained stable regardless of the CO2 source tested. Carbon Dioxide Utilisation Efficiency (CO2UE) was 53.8% (S1), 24.1% (S2), and 41.4% (S3), respectively. The results indicate that the presence of SOx in exhaust gases negatively affects the growth and survival of C. vulgaris, while its removal improves both biomass productivity and CO2 sequestration efficiency. The research demonstrates the potential for integrating microalgae cultivation with industrial CO2 emission management.