Thermal pretreatment and bioaugmentation improve methane yield of microalgal mix produced in thermophilic anaerobic digestate

Lavrič, Lea; Cerar, Ana; Fanedl, Lijana; Lazar, Borut; Žitnik, Miha; Logar, Romana Marinšek

doi:10.1016/j.anaerobe.2017.02.001

Cited by 15 publications

(6 citation statements)

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“…Successful AD of algal biomass depends on the efficient deconstruction of the cell wall (Córdova et al, 2018). Physical, mechanical, chemical, and thermal pre-treatment methods have been tested to enhance digestion efficiency (Alzate et al, 2012;Lam and Lee, 2012;Passos et al, 2013Passos et al, , 2014Passos et al, , 2018Lavrič et al, 2017). These methods could improve biogas yield, but the energy input is quite high (Carrere et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Characterization of Core Microbiomes and Functional Profiles of Mesophilic Anaerobic Digesters Fed With Chlorella vulgaris Green Microalgae and Maize Silage

et al. 2019

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Microalgal biomass is an alternative feedstock for biogas production although its C/N ratio is usually lower than optimal, therefore co-fermentation is recommended. Biogas production from photoautotrophically grown Chlorella vulgaris (C. vulgaris) biomass (240 mL CH 4 g oTS −1 ) and co-fermentation with maize silage (330 mL CH 4 g oTS −1 ) has been studied in semi continuous laboratory biogas fermenters. Maize silage control yielded 310 mL CH 4 g oTS −1 . The microbial community and the read-based functional profiles, derived from these data, were examined during the process by using next-generation metagenome Ion Torrent sequencing technology. The read-based core microbiome consisted of 92 genera from which 60 abundant taxa were directly associated with the microbial methane producing food chain. The data-set was also analyzed in a genome-based approach. Sixty-five bins were assembled, 52 of them belonged in the core biogas producing genera identified by the read-based metagenomes. The read-based and genome-based approaches complemented and verified each other. The functional profiles indicated a variety of glycoside hydrolases. Substantial rearrangements of the methanogen functions have also been observed. Co-fermentation of algal biomass and plant biomass can be carried out for an extended period of time without process failure. The microbial members of the inoculum are well-conserved, feedstock composition changes caused mostly relative abundance alterations in the core microbiome.

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Section: Introductionmentioning

confidence: 99%

Characterization of Core Microbiomes and Functional Profiles of Mesophilic Anaerobic Digesters Fed With Chlorella vulgaris Green Microalgae and Maize Silage

et al. 2019

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“…The green microalgae Chlorella vulgaris was digested in a batch system with the consequent 24.0% increase of the methane yield [6]. A later study by Lavric and co-workers using the same strain achieved a 62.0% biodegradation of a microalgal mix from a high-rate algal pond, yet including a thermal pre-treating step for disruption [7]. These interesting strategies are microbial based and therefore promising but lack relevant information about their viability in continuous systems like high retention anaerobic digesters.…”

Section: Introductionmentioning

confidence: 99%

Thermophilic anaerobic conversion of raw microalgae: Microbial community diversity in high solids retention systems

et al. 2019

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“…Munoz et al studied the effect of cellulase produced by Raoultella ornithinolytica to Nannochloropsis gaditana biomass and observed 140% to 158% enhancement in biogas yield. In a research conducted by Lavric et al, it was found that bioaugmentation of mix microalgal biomass with anaerobic bacteria ( Clostridium thermocellum ) at thermophilic conditions (55°C) had increased amount of biogas produced as 12%. The research on producing on‐site enzymes by microorganisms and co‐cultivation should be further evaluated to provide a cost‐efficient pretreatment method.…”

Section: Pretreatment Methods Applied To Microalgal Biomassmentioning

confidence: 99%

A comprehensive review on pretreatment of microalgae for biogas production

Çakmak

Uğurlu

2018

Int J Energy Res

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Summary Use of microalgal biomass for renewable energy production has gained considerable attention in the world due to increasing global energy demand and negative environmental impacts of nonrenewable fossil fuels. Anaerobic digestion is one of the renewable technologies that microalgal biomass is converted into biogas by anaerobic archea. One of the main drawbacks of using microalgal biomass for biogas production is that certain types of microalgae has rigid cell wall characteristics, which limits accessibility of anaerobic archea to microalgal intracellular organic matter during hydrolysis phase. This limitation lowers efficiency of biogas production from microalgal biomass. However, introducing pretreatment methods prior to anaerobic digestion provides disruption of rigid microalgal cell wall and improve biogas yields from microalgal biomass. The objective of this paper was to review current knowledge related to pretreatment methods applied prior to anaerobic digestion of microalgal biomass. Efficiency and applicability of pretreatment methods mainly depend on type of microalgae, cell wall characteristics, and cost and energy requirements during pretreatment process. In this review, various type of pretreatment methods applied to microalgal biomass was discussed in detail with background knowledge and literature studies in their potential on maximization of biogas yields and their cost effectiveness, which is important for large‐scale applications. In the view of current knowledge, it was concluded that each pretreatment method has a relative contribution to improvement in biogas production depending on the type of microalgae. However, energy and cost requirements are the main limitations for pretreatment. So, further studies should focus on reduction of cost and energy demand by introducing combined methods, novel chemicals, and on‐site or immobilized enzymes in pretreatment to increase feasibility of pretreatment prior to anaerobic digestion in industrial scale.

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Thermal pretreatment and bioaugmentation improve methane yield of microalgal mix produced in thermophilic anaerobic digestate

Cited by 15 publications

References 36 publications

Characterization of Core Microbiomes and Functional Profiles of Mesophilic Anaerobic Digesters Fed With Chlorella vulgaris Green Microalgae and Maize Silage

Characterization of Core Microbiomes and Functional Profiles of Mesophilic Anaerobic Digesters Fed With Chlorella vulgaris Green Microalgae and Maize Silage

Thermophilic anaerobic conversion of raw microalgae: Microbial community diversity in high solids retention systems

A comprehensive review on pretreatment of microalgae for biogas production

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