A Review of Microalgal Biofilm Technologies: Definition, Applications, Settings and Analysis

Osorio, Jairo Hernán Moreno; Pollio, Antonino; Frunzo, Luigi; Lens, P.N.L.; Esposito, Giovanni

doi:10.3389/fceng.2021.737710

Cited by 48 publications

(14 citation statements)

References 254 publications

(414 reference statements)

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“…In contrast to planktonic cultures, the biofilm and gel-immobilised cultures share similarities in terms of higher biomass production and harvesting simplicity (1, 50). We, therefore, compared the capacity of the total areal biomass production per volume in these two configurations.…”

Section: Resultsmentioning

confidence: 99%

Light management by algal aggregates in living photosynthetic hydrogels

Chua,

Smith,

Murthy

et al. 2023

Preprint

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Rapid progress in algal biotechnology has triggered a growing interest in hydrogel-encapsulated microalgal cultivation, especially for the engineering of functional photosynthetic materials and biomass production. An overlooked characteristic of gel-encapsulated cultures is the emergence of cell aggregates, which are the result of the mechanical confinement of the cells. Such aggregates have a dramatic effect on the light management of gel-encapsulated photobioreactors and hence strongly affect the photosynthetic outcome. In order to evaluate such an effect, we experimentally studied the optical response of hydrogels containing algal aggregates and developed optical simulations to study the resultant light intensity profiles. The simulations are validated experimentally via transmittance measurements using an integrating sphere and aggregate volume analysis with confocal microscopy. Specifically, the heterogeneous distribution of cell aggregates in a gel matrix can increase light penetration while alleviating photoinhibition compared to a flat biofilm. Finally, we demonstrate that light harvesting efficiency can be further enhanced with the introduction of scattering particles within the hydrogel matrix, leading to a four-fold increase in biomass growth. Our study, therefore, highlights a new strategy for the design of spatially efficient photosynthetic living materials that have important implications for the engineering of future algal cultivation systems.Significance StatementThe ability to cultivate microalgae at scale efficiently would allow more sustainable production of food and food additives. However, efficient growth of microalgae requires optimised light conditions, which are usually challenging to obtain using biofilm cultivations mode: as the outer layer of cells are necessarily more exposed to incoming light than the inner layer, posing the problem of photoinhibition on the outer cells receiving too much light, and shading the ones below. Here we study both experimentally and numerically, how microalgae aggregates growing in the confinement of a hydrogel can provide an improved light distribution and therefore biomass growth is maximised. This study proposes new strategies on how to engineer future photobioreactors.

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Section: Resultsmentioning

confidence: 99%

Light management by algal aggregates in living photosynthetic hydrogels

Chua,

Smith,

Murthy

et al. 2023

Preprint

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“…The cultivation of microalgae in biofilm reactors involves immobilizing the microalgae on a surface that acts as a support, forming a continuous layer. This method offers advantages such as higher concentration per unit volume of medium, reduction or absence of cells in the effluent, and ease of harvesting [37]. The extraction and dewatering of algae cells from biofilms are simplified by the ease of separating attached cells from their growth medium.…”

Section: Biofilm Reactorsmentioning

confidence: 99%

The Microalgae <em>Chlamydomonas </em>for Bioremediation and Bioproduct Production

Bellido-Pedraza,

Torres,

Llamas

2024

Preprint

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The extensive metabolic diversity of microalgae, coupled with their rapid growth rates and cost-effective production, position these organisms as highly promising resources for a wide range of biotechnological applications. These characteristics allow microalgae to address crucial needs in both the agricultural, medical, and industrial sectors. Microalgae are proving to be val-uable in various fields, including the remediation of diverse wastewater types, the production of biofuels and biofertilizers, and the extraction of various products from their biomass. For decades, the microalga Chlamydomonas has been widely used as a fundamental research model organism in various areas such as photosynthesis, respiration, sulfur and phosphorus metabolism, nitrogen metabolism, and flagella synthesis, among others. However, in recent years, the potential of Chlamydomonas as a biotechnological tool for bioremediation, biofertilization, biomass, and bio-products production has been increasingly recognized. Bioremediation of wastewater using Chlamydomonas presents significant potential for sustainable reduction of contaminants and fa-cilitates resource recovery and valorization of microalgal biomass, offering important economic benefits. Chlamydomonas has also established itself as a platform for the production of a wide va-riety of biotechnologically interesting products, such as different types of biofuels, and high-value-added products. The aim of this review is to achieve a comprehensive understanding of the potential of Chlamydomonas in these aspects, and to explore their interrelationship, which would offer significant environmental and biotechnological advantages.

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“…Among them, cotton and jute fabric were found to be highly effective support materials for microalgal biofilms. 35 Microalgae grown on the rotating biofilm can be harvested by simply scraping the microalgae from fabric film in a continuous mode significantly reducing the cost associated with harvesting microalgae from water. Some of the disadvantages of RAB over the conventional suspended growth methods include CO 2 mass transfer in water and lighting requirements.…”

Section: Cultivation Harvesting and Processing Of Microalgaementioning

confidence: 99%