Biofilm reactors for value-added products production: An in-depth review

Germeç, Mustafa; Demirci, Ali; Turhan, İrfan

doi:10.1016/j.bcab.2020.101662

Cited by 43 publications

(19 citation statements)

References 212 publications

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“…As observed from the FESEM images, the intracellular adhesion behavior of microalgal cells during nanoemulsion-based cultivation opens the possibility of exploring biofilm-based systems. The intracellular adhesion and cellular colonization are the most influential parameter for biofilm formation [ 95 ]. The cellular colonization restricts temporary immobilization of cells and ensures cellular bridging which increases the cell density and promotes thickening of biofilm which might help in gaining biomass yield and value-added products [ 96 ].…”

Section: Resultsmentioning

confidence: 99%

A novel nanoemulsion-based microalgal growth medium for enhanced biomass production

Nigam¹,

Pant²,

Singh

2021

Biotechnol Biofuels

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Background Microalgae are well-established feedstocks for applications ranging from biofuels to valuable pigments and therapeutic proteins. However, the low biomass productivity using commercially available growth mediums is a roadblock for its mass production. This work describes a strategy to boost algal biomass productivity by using an effective CO2 supplement. Results In the present study, a novel nanoemulsion-based media has been tested for the growth of freshwater microalgae strain Chlorella pyrenoidosa. Two different nanoemulsion-based media were developed using 1% silicone oil nanoemulsion (1% SE) and 1% paraffin oil nanoemulsion (1% PE) supplemented in Blue-green 11 media (BG11). After 12 days of cultivation, biomass yield was found highest in 1% PE followed by 1% SE and control, i.e., 3.20, 2.75, and 1.03 g L−1, respectively. The chlorophyll-a synthesis was improved by 76% in 1% SE and 53% in 1% PE compared with control. The respective microalgal cell numbers for 1% PE, 1% SE and control measured using the cell counter were 3.00 × 106, 2.40 × 106, and 1.34 × 106 cells mL−1. The effective CO2 absorption tendency of the emulsion was highlighted as the key mechanism for enhanced algal growth and biomass production. On the biochemical characterization of the produced biomass, it was found that the nanoemulsion-cultivated C. pyrenoidosa had increased lipid (1% PE = 26.80%, 1% SE = 23.60%) and carbohydrates (1% PE = 17.20%, 1% SE = 18.90%) content compared to the control (lipid = 18.05%, carbohydrates = 13.60%). Conclusions This study describes a novel nanoemulsion which potentially acts as an effective CO2 supplement for microalgal growth media thereby increasing the growth of microalgal cells. Further, nanoemulsion-cultivated microalgal biomass depicts an increase in lipid and carbohydrate content. The approach provides high microalgal biomass productivity without altering morphological characteristics like cell shape and size as revealed by field emission scanning electron microscope (FESEM) images. Graphical abstract

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Section: Resultsmentioning

confidence: 99%

A novel nanoemulsion-based microalgal growth medium for enhanced biomass production

Nigam¹,

Pant²,

Singh

2021

Biotechnol Biofuels

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“…On one hand, the concentration of cell-associated hydrolytic enzymes at the biofilm-substrate interface can be increased to improve saccharification [ 53 , 54 ]. On the other hand, symbiotic biofilms, which consists of aerobic fungi (e.g., T. reesei ) and anaerobic bacteria (e.g., L. pentosus ), is an ideal strategy for simultaneous (hemi) cellulose hydrolysis and products (e.g., lactic acid) generation [ 55 , 56 ]. Beyond QS signal molecules, a large repertoire of metabolites are actively or passively diffused among microorganisms to establish cell–cell interactions, including small (e.g., H 2 , CH 4 , CO 2 , and lactate) and large molecules (peptides and proteins) (Fig.…”

Section: Microbial Interaction Modes and Molecular Mechanismsmentioning

confidence: 99%

“…Various microbial spatial and temporal segregations exist in nature. For example, aerobic and anaerobic microbial populations are separated by oxic/anoxic niches [ 22 ], whereas biofilms provide structured microenvironments [ 53 , 56 , 79 , 80 ]. Such spatial organization of microbes generates locally heterogeneous subpopulations, which can acquire different resources, and further enhance local interactions.…”

Section: Synthetic Ecology Provides An Opportunity To “Bottom-up” Design Synthetic Microbial Consortia For Efficient Lignocellulose Biocomentioning

confidence: 99%

Bottom-up synthetic ecology study of microbial consortia to enhance lignocellulose bioconversion

Lin

2022

Biotechnol Biofuels

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Lignocellulose is the most abundant organic carbon polymer on the earth. Its decomposition and conversion greatly impact the global carbon cycle. Furthermore, it provides feedstock for sustainable fuel and other value-added products. However, it continues to be underutilized, due to its highly recalcitrant and heterogeneric structure. Microorganisms, which have evolved versatile pathways to convert lignocellulose, undoubtedly are at the heart of lignocellulose conversion. Numerous studies that have reported successful metabolic engineering of individual strains to improve biological lignin valorization. Meanwhile, the bottleneck of single strain modification is becoming increasingly urgent in the conversion of complex substrates. Alternatively, increased attention has been paid to microbial consortia, as they show advantages over pure cultures, e.g., high efficiency and robustness. Here, we first review recent developments in microbial communities for lignocellulose bioconversion. Furthermore, the emerging area of synthetic ecology, which is an integration of synthetic biology, ecology, and computational biology, provides an opportunity for the bottom-up construction of microbial consortia. Then, we review different modes of microbial interaction and their molecular mechanisms, and discuss considerations of how to employ these interactions to construct synthetic consortia via synthetic ecology, as well as highlight emerging trends in engineering microbial communities for lignocellulose bioconversion.

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“…Biofilm formation can be considered a bacterial adaptive strategy in that it permits survival compared with planktonic forms in the form of resistance to environmental stresses [56]. In addition, biofilm can be a sustainable alternative in the recovery of environments contaminated by toxic pollutants [54]. .…”

Section: Biofilm Formation By Pseudomonas Fluorescens Cma55mentioning

confidence: 99%

Specific quorum sensing molecules are possibly associated with responses to herbicide toxicity in aPseudomonasstrain

Pileggi

Freitas

Rovida

et al. 2020

Preprint

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Pesticides contribute to pest control and increased agricultural production; however, they are toxic to non-target organisms and they contaminate the environment. The exposure of bacteria to these substances can lead to the need for physiological and structural changes for survival, which can be determined by genes whose expression is regulated by quorum sensing (QS). However, it is not yet clear whether these processes can be induced by herbicides. Thus, the aim of this work was to determine whether there is a QS response system in a Pseudomonas fluorescens strain that is modulated by herbicides. This strain was isolated from water storage tanks used for washing pesticide packaging and was tested against herbicides containing saflufenacil, glyphosate, sulfentrazone, 2,4-D, and dicamba as active molecules. We found that this strain possibly uses QS signaling molecules to control the production of reactive oxygen species, whether those produced by the bacterium’s energy generating system or by molecules induced by the presence of saflufenacil and glyphosate. This strain used other signaling molecules for various stages of biofilm formation in the presence of herbicides containing sulfentrazone, 2,4-D, and dicamba. These findings, as an initial screening which will guide new studies, suggest that this strain has a flexibility in gene expression that allows survival in the presence of several stress-inducing molecules, regardless of previous exposure. This represents a model of metabolic and physiological plasticity. Biofilms made up of several bacterial species can use this model in agricultural environments, increasing the potential for degradation of xenobiotics, but with impacts on diversity and functionality of microbiotas in these environments.

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Biofilm reactors for value-added products production: An in-depth review

Cited by 43 publications

References 212 publications

A novel nanoemulsion-based microalgal growth medium for enhanced biomass production

A novel nanoemulsion-based microalgal growth medium for enhanced biomass production

Bottom-up synthetic ecology study of microbial consortia to enhance lignocellulose bioconversion

Specific quorum sensing molecules are possibly associated with responses to herbicide toxicity in aPseudomonasstrain

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