Anaerobic digestion of microalgal biomass: Challenges, opportunities and research needs

González‐Fernández, Cristina; Sialve, Bruno; Molinuevo-Salces, Beatriz

doi:10.1016/j.biortech.2015.09.095

Cited by 160 publications

(56 citation statements)

References 72 publications

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“…Among the substrates that can be used for AD, microalgae arise as a promising feedstock due to their fast growth, their ability to thrive in residual effluents or the non‐necessity of arable lands. AD of microalgae for biogas production has been intensively investigated over the last decade and the main bottlenecks have been identified . One of the main drawback of using microalgae as feedstock for AD is the robust cell wall exhibited by some strains, preventing organic matter accessibility to bacteria attack .…”

Section: Introductionmentioning

confidence: 99%

Volatile fatty acids production from protease pretreated Chlorella biomass via anaerobic digestion

Magdalena

Tomás‐Pejó

Ballesteros

et al. 2018

Biotechnology Progress

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Volatile fatty acids (VFAs) produced via anaerobic digestion (AD) are regarded as a low cost production process of building blocks of interest for the chemical industry. In this study, VFAs and methane production were assessed in batch reactors at different temperature ranges (psychrophilic 25°C, mesophilic 35°C, thermophilic 50°C) and different pH values (5.5 and 7.5) using protease pretreated Chlorella sp. biomass as substrate. Acetic acid and propionic acid were the most abundant products (up to 73% of the total VFAs) during the first days independently of the conditions. VFAs concentration decreased over time as methane was produced after a lag phase of 7–10 days. Results showed that best conditions for VFAs production were mesophilic temperature ranges (35°C) at neutral initial pH values (7.5), and psychrophilic temperature ranges (25°C) at low initial pH values (5.5) which resulted in a conversion of the initial COD into VFAs of 48%, respectively. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1363–1369, 2018

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Section: Introductionmentioning

confidence: 99%

Volatile fatty acids production from protease pretreated Chlorella biomass via anaerobic digestion

Magdalena

Tomás‐Pejó

Ballesteros

et al. 2018

Biotechnology Progress

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“…One crucial factor is the differences in structure of microalgae cell walls. The role of the cell wall in the microbial degradability of algae biomass is highlighted in many investigations [6,13,37,38,[40][41][42][43]. Many microalgae species (e.g.…”

Section: Pretreatmentmentioning

confidence: 99%

“…General insights from these studies are: (1) pretreatment methods are species-specific and their success depends on the nature of the cell wall; (2) mechanical pretreatments which consume electricity are more energy intensive than thermal, chemical and enzyme pretreatments; (3) chemical pretreatments usually have a low cost but produce inhibitory substances which could hamper the AD process; (4) for pretreatment mechanisms such as disruption of microalgal cell walls, the synergistic effects of the enzymes need further investigation; (5) combined pretreatments may provide energy and cost-effective options; (6) multi-objective optimization techniques could be used to obtain a high biogas yield with a positive energy balance; (7) enzyme/biological pretreatments have high selectivity, low inhibitory effects and higher probability of positive energy return [147]; (8) research on pilot/demonstration scale pretreatments is rare; (9) thermal pretreatments have been employed widely and proven to be the most efficient in microalgae pretreatment for AD; and (10) a detailed economic/energy analysis of microalgal AD for biogas production with pretreatment is still missing. The capital cost of the anaerobic digester could be reduced by using reactors designed for high OLR and low HRT [37]. The OLRs are typically between 1 and 6 g VS/L/d while the HRT varies between 10 and 30 days [37,38].…”

Section: Pretreatmentmentioning

confidence: 99%

“…The capital cost of the anaerobic digester could be reduced by using reactors designed for high OLR and low HRT [37]. The OLRs are typically between 1 and 6 g VS/L/d while the HRT varies between 10 and 30 days [37,38]. Although high OLR will increase the methane productivity, overloading will decrease the biogas production efficiency due to the accumulation of inhibitors such as ammonia and acids [6,37,38].…”

Section: Pretreatmentmentioning

confidence: 99%

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Techno-Economic Analysis of Biogas Production from Microalgae through Anaerobic Digestion

Wu¹,

Moreira²,

Zhang³

et al. 2019

Anaerobic Digestion

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Microalgae are a promising feedstock for bioenergy due to higher productivity, flexible growing conditions, and high lipid/polysaccharide content compared to terrestrial biomass. Microalgae can be converted to biogas through anaerobic digestion (AD). AD is a mature technology with a high energy return on energy invested. Microalgae AD can bypass energy intensive dewatering operations that are associated with liquid fuel production from algae. A techno-economic assessment of the commercial feasibility of algae-based biogas production was conducted using Cyanothece BG0011 biomass as an example. BG0011 is a naturally occurring, saline cyanobacterium isolated from Florida Keys. It fixes atmospheric nitrogen and produces exopolysaccharide (EPS). Maximum cell density and EPS concentration of 2.7 and 2.1 g afdw 1 /L (for total algae biomass concentration of 4.8 g afdw/L) were obtained by air sparging. For an areal cell and EPS productivity of 12.4 and 9.6 g afdw/m2/day, respectively, the biomethane production cost was 14.8 $/MMBtu using covered anaerobic lagoon and high-pressure water scrubbing for biogas purification. Electricity production from biogas costs 13 cents/kwh. If areal productivity was increased by 33% from the same system, by sparging air enriched with 1% CO2, then biomethane cost was reduced to 12.16 $/MMBtu and electricity cost to 11 cents/kwh.

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“…The most probable option for converting and recovering cyanobacterial and microalgal biomass‐contained nitrogen and phosphorous is anaerobic digestion (AD) . AD is a well‐established method for converting complex organic matter into methane and CO 2 . An overview of the processes involved in the AD of microalgae and cyanobacteria can be found in a review by Gonzalez‐Fernandez et al Reasons that AD is an attractive option for recovering photoautotrophic microbial biomass include: the methane produced from AD could be used to supplement the energy requirements of the production facility, the CO 2 produced could be used for microalgae and cyanobacteria cultivation, and the ammonia and phosphorous containing effluent could be recycled to recover the nutrients .…”

Section: Improvements To Cultivation Mediummentioning

confidence: 99%

Photobioreactor cultivation strategies for microalgae and cyanobacteria

Johnson

Katuwal

Anderson

et al. 2018

Biotechnology Progress

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The current burden on fossil-derived chemicals and fuels combined with the rapidly increasing global population has led to a crucial need to develop renewable and sustainable sources of chemicals and biofuels. Photoautotrophic microorganisms, including cyanobacteria and microalgae, have garnered a great deal of attention for their capability to produce these chemicals from carbon dioxide, mineralized water, and solar energy. While there have been substantial amounts of research directed at scaling-up production from these microorganisms, several factors have proven difficult to overcome, including high costs associated with cultivation, photobioreactor construction, and artificial lighting. Decreasing these costs will substantially increase the economic feasibility of these production processes. Thus, the purpose of this review is to describe various photobioreactor designs, and then provide an overview on lighting systems, mixing, gas transfer, and the hydrodynamics of bubbles. These factors must be considered when the goal of a production process is economic feasibility. Targets for improving microalgae and cyanobacteria cultivation media, including water reduction strategies will also be described. As fossil fuel reserves continue to be depleted and the world population continues to increase, it is imperative that renewable chemical and biofuel production processes be developed toward becoming economically feasible. Thus, it is essential that future research is directed toward improving these processes. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:811-827, 2018.

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Anaerobic digestion of microalgal biomass: Challenges, opportunities and research needs

Cited by 160 publications

References 72 publications

Volatile fatty acids production from protease pretreated Chlorella biomass via anaerobic digestion

Volatile fatty acids production from protease pretreated Chlorella biomass via anaerobic digestion

Techno-Economic Analysis of Biogas Production from Microalgae through Anaerobic Digestion

Photobioreactor cultivation strategies for microalgae and cyanobacteria

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