Biochemical and Morphological Characterization of Heterotrophic <i>Crypthecodinium cohnii</i> and <i>Chlorella vulgaris</i> Cell Walls

Canelli, Greta; Martínez, Patricia Murciano; Austin, Sean; Ambühl, Mark E.; Dionisi, Fabiola; Bolten, Christoph J.; Carpine, Roberta; Neutsch, Lukas; Mathys, Alexander

doi:10.1021/acs.jafc.0c05032

Cited by 34 publications

(41 citation statements)

References 46 publications

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“…Figure 4 shows the individual carbohydrate split obtained from HPLC analysis. High levels of glucuronic acid, an integral building block of the algal cell wall, which decreased with increasing temperature, were detected in hydrolysates from both standard and scCO 2 treated algal biomass [ 23 , 24 , 25 ]. In contrast to glucuronic acid, the concentration of mannitol, levoglucosan and xylose was much lower but, nevertheless, increased with increasing temperature, peaking at 160 °C (standard method, levoglucosan), 180 °C (standard method, mannitol) and 200 °C (standard method, xylose).…”

Section: Resultsmentioning

confidence: 99%

Microwave-Assisted Defibrillation of Microalgae

et al. 2021

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The first production of defibrillated celluloses from microalgal biomass using acid-free, TEMPO-free and bleach-free hydrothermal microwave processing is reported. Two routes were explored: i. direct microwave process of native microalgae (“standard”), and ii. scCO2 pre-treatment followed by microwave processing. ScCO2 was investigated as it is commonly used to extract lipids and generates considerable quantities of spent algal biomass. Defibrillation was evidenced in both cases to afford cellulosic strands, which progressively decreased in their width and length as the microwave processing temperature increased from 160 °C to 220 °C. Lower temperatures revealed aspect ratios similar to microfibrillated cellulose whilst at the highest temperature (220 °C), a mixture of microfibrillated cellulose and nanocrystals were evidenced. XRD studies showed similar patterns to cellulose I but also some unresolved peaks. The crystallinity index (CrI), determined by XRD, increased with increasing microwave processing temperature. The water holding capacity (WHC) of all materials was approximately 4.5 g H2O/g sample. The materials were able to form partially stable hydrogels, but only with those processed above 200 °C and at a concentration of 3 wt% in water. This unique work provides a new set of materials with potential applications in the packaging, food, pharmaceutical and cosmetic industries.

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Section: Resultsmentioning

confidence: 99%

Microwave-Assisted Defibrillation of Microalgae

et al. 2021

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“…Thus this could mean that ß -glucans form a large part of the polysaccharidic fraction of the cell wall, and the slight decrease in polysaccharides that we observe in stationary phase and in saline stress conditions compared to exponential phase (XPS data) may be due to the decrease in these conditions of these types of polysaccharides. Glucose is also the monomer constituting cellulose, however, Gerken et al found that cellulase enzyme had no activity on C. vulgaris cells, meaning that this strain most likely does not contain cellulose, in contrast with other microalgae species [9,54]. Finally, the activity of pectinase and sulphatase enzymes found by Gerken et al , could explain the presence of rhamnose, arabinose and galactose in our analysis, which could be part of pectic substances (rhamnose and arabinose) and of proteoglycans or glycosaminoglycans (galactose).…”

Section: Resultsmentioning

confidence: 99%

Combining AFM, XPS and chemical hydrolysis to understand the complexity and dynamics of C. vulgaris cell wall composition and architecture

Demir-Yilmaz

Schiavone

Esvan

et al. 2022

Preprint

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The microalgae cell wall represents its interface with its environment and a strong barrier to disrupt in order to extract the cell products. Understanding its composition and architecture is a challenge that if overcome, could lead to substantial advancements in optimizing microalgae-production systems. However, the cell wall is a dynamic and complex structure that evolves depending on the growth phase or culture conditions. To apprehend this complexity, an experimental approach combining AFM, XPS, and chemical hydrolysis followed by HPAEC-PAD was developed to understand the cell wall of Chlorella vulgaris, a biotechnologically-relevant green microalgae species. Exponential and stationary growth stages were investigated, as well as saline stress condition inducing lipid production. Results showed that both the cell wall composition and architecture changes in stationary phase, with an increase of the lipidic fraction at the expanse of the proteic fraction, changes in the polysaccharidic composition, and a significant increase of its rigidity. Under saline stress, cell wall architecture seems to be affected as its rigidity decreases importantly. Altogether, this study demonstrates the power of combining these three techniques to give new insights into C. vulgaris cell wall, in terms of composition and architecture, and of its dynamics in different conditions.

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“…A8J3T4 has hydrolase activity, and it is reported to act on carbon-nitrogen (but not peptide) bonds. This protein is also related to poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase activity, which can be associated with the deacetylation of N-glucosamine present in the C. vulgaris cell wall (Canelli, Murciano Martínez, Austin, et al, 2021). Similarly, A0A2K3D822 was selected because of its hydrolytic activity, which may be carried out on the C. vulgaris cell wall.…”

Section: Proteomic Analysis Of Secreted Proteinsmentioning

confidence: 99%

Pulsed Electric Field Treatment Enhances Lipid Bioaccessibility While Preserving Oxidative Stability in Chlorella Vulgaris

Canelli¹,

Kuster²,

Jaquenod³

et al. 2022

Proceedings of 2022 AOCS Annual Meeting &Amp; Expo

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There is growing demand for gentle technologies to improve the lipid bioaccessibility (BA) of Chlorella vulgaris biomass while preserving cell integrity and therefore oxidative stability. Pulsed electric field treatment (PEF, 5 μs at 20 kV cm − 1 , 31.8 kJ kg − 1 sus ) led to an enhancement in lipid BA from 4-7.8% (untreated) to 18.7-20.9%. To reach such a level of BA, incubation in buffer after the treatment (12 h at 25/37 • C, 48 h at 4 • C) was required. As hypothesized, PEF preserved cell integrity, as shown by particle size and scanning electron microscopy analyses, as well as oxidative stability of the biomass over 3 months at 40 • C. Proteome analysis identified four proteins that may be involved in cell wall lytic activity during incubation after PEF. Future work should focus on further understanding the mechanism behind incubation after PEF and studying the potential effect played by endogenous cell wall-degrading enzymes.

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Biochemical and Morphological Characterization of Heterotrophic Crypthecodinium cohnii and Chlorella vulgaris Cell Walls

Cited by 34 publications

References 46 publications

Microwave-Assisted Defibrillation of Microalgae

Microwave-Assisted Defibrillation of Microalgae

Combining AFM, XPS and chemical hydrolysis to understand the complexity and dynamics of C. vulgaris cell wall composition and architecture

Pulsed Electric Field Treatment Enhances Lipid Bioaccessibility While Preserving Oxidative Stability in Chlorella Vulgaris

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