Fengzheng Gao


Last Name

Gao

First Name

Fengzheng

ORCID

0000-0003-1080-809X

Organisational unit

09571 - Mathys, Alexander / Mathys, Alexander

Filters

2023 - 202535
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Publications 1 - 10 of 35
  • Dunaliella production in China
    Item type: Presentation
    Gao, Fengzheng (2023)
  • Spatially dependent microalgal lipid production in a membrane biofilm reactor
    Item type: Other Conference Item
    Hoffmann, Tobias; Archer, Lorraine; Baumgartner, Julia; et al. (2024)
    Microalgae are a promising source of lipids that can be used for fuel and/or human/animal nutrition. However, realization of such microalgae based processes is hampered by low cell concentrations in standard suspension cultures. Additionally, as lipid production in microalgae is only induced by nutrient limitation, for example nitrogen-depletion, culture conditions must be adjusted on a temporal scale in the form of inefficient batch production. To address these challenges, we present here an immobilized cultivation system wherein Chlamydomonas reinhardtii is grown on a transparent, gas permeable, flatsheet membrane within a bioreactor. Light, oxygen and CO2 (from ambient air) as well as ammonia are provided through the membrane. This system promotes microalgal growth directly on the membrane in the form of a biofilm, which possesses much higher cell density vis-à-vis suspended cultures. This system also results in the formation of various niches (i.e., spatially dependent physiological behavior presented by the algae) that are a result of the concentration gradients of light and nutrients across the biofilm. Ultimately, this spatial heterogeneity enables the transformation of temporal scale lipid production into a spatially dependent continuous system. Specifically, cells show high growth activity close to the membrane where nutrients and light are readily available while cells further away from the membrane would experience nutrient limitation and therefore accumulate lipids. These peripheral cells could then be harvested in-situ while the active growth zone towards the membrane remains unperturbed. In this work, we will demonstrate the formation of a nitrogen gradient and the biological response to it by directly measuring the ammonium concentration in the biofilm using microsensors as well as via lipid staining and through use of engineered fluorescent reporter strains sensitive to nitrogen deficiency. Besides these experimental results, we will present a computational model of this interdependent dynamic of nutrient gradient formation and cell physiology within our system.
  • Microalgae as more sustainable and affordable micronutrient-rich sources for humans
    Item type: Other Conference Item
    Gao, Fengzheng; Zimmermann, Michael; von Meyenn, Ferdinand; et al. (2024)
  • Microalgae in human nutrition and health: using microalgae for iron-deficiency anaemia treatment
    Item type: Other Conference Item
    Gao, Fengzheng; Zimmermann, Michael; von Meyenn, Ferdinand; et al. (2023)
  • Bioaccessibility, bioavailability, and bioactivity assessment of microalgae-derived products for human nutrition and health
    Item type: Other Conference Item
    Gao, Fengzheng; Zimmermann, Michael; von Meyenn, Ferdinand; et al. (2024)
  • Microalgae Production and Application
    Item type: Other Conference Item
    Gao, Fengzheng (2023)
  • Microalgae as more sustainable and affordable sources for micronutrient deficiency treatment
    Item type: Other Conference Item
    Gao, Fengzheng; Zimmermann, Michael; von Meyenn, Ferdinand; et al. (2024)
  • Growth kinetic model of Chlorella vulgaris in a dark biogas slurry culture system based on a light attenuation model
    Item type: Journal Article
    Liu, Xueyan; Chen, Chaorui; Lu, Haifeng; et al. (2025)
    Algal Research
    Using biogas slurry to culture microalgae can realize pollutants transformation into useful biomass, it has been attracted by the whole recycling-oriented society and low-carbon effect. However, the dark color of biogas slurry caused light attenuation, which weakened the light provision for microalgal growth. In this work, the microalgal growth models of dark color biogas slurry-microalgae cultivation system (DBS-M) were established. Results showed that chroma can be introduced in Lambert-Beer Law for describing the rules of light condition changes. While microalgal cells concentration contribute more light attenuation effect compared with chroma: the degree of light attenuation caused by 1000 Hazen's dark biogas slurry is equivalent to that by 0.18gL⁻¹ biomass. The dynamic changes of biomass concentration and the light attenuation model in DBS-M can also be combined with average light intensity to form the optimal Pearl-Monod (PM) model for predicting microalgal growth, which can respond to the changes of optical path (different photobioreactors) and biomass concentration in real production system. This further improves the accuracy and universality of the models. According to the above models, 5 cm is desirable PBRs optical path. Under this condition, with the initial biomass was below 0.4gL⁻¹ and I0 was 240–480 μmolm⁻²s⁻¹, μ of C. vulgaris reached above 1.0d⁻¹. Finally, a semi-continuous culture strategy for C. vulgaris growth in biogas slurry and an average daily yield (P) model was established. According to the model, the highest P reached 0.186 g L⁻¹d⁻¹ when the daily initial biomass was maintained at 0.375 g L⁻¹d⁻¹ under the semi-continuous culture, which was 23.75 % higher than that of the sequencing batch. This work might be helpful for the operation of dark color biogas slurry-microalgae cultivation system in large scale in the future.
  • Microalgae R&D in Europe
    Item type: Presentation
    Gao, Fengzheng (2023)
  • Aqueous extraction and properties of lipid droplets from the cell wall deficient microalga Chlamydomonas reinhardtii
    Item type: Other Conference Item
    Baumgartner, Julia; Chua, Sing Teng; Blunier, Maylin; et al. (2024)
    Plant-based lipid droplets (LDs) have potential as natural emulsions. LDs can be extracted aqueously and are stable over long time to be directly integrated to food and other products (Abdullah et al., 2020; Nikiforidis, 2019). Research on microalgal LDs has gained momentum due to increasing interest in microalgae-derived lipids and other chemicals (Goold et al., 2015; Tsai et al., 2015; Wang et al., 2009). However, little is known of the LDs techno-functional properties. Furthermore, microalgal lipids are primarily extracted with organic solvents (Russell et al., 2022). Aqueous LDs extraction can decrease energy demand, being a solvent-free, wet process (Russell et al., 2022; Veerasamy et al., 2024; Weschler et al., 2014). We investigated both aqueous extraction of LDs from the cell wall deficient microalga Chlamydomonas reinhardtii and the LDs techno-functional properties. Lipid accumulation was induced by natural onset of nitrogen starvation in a photoautotrophic and urea-based medium. A stationary dry weight (DW) of 6 g L-1 was reached after 5 days of growth, and the lipid content increased from 9.7 ± 0.6 % of DW on day 5 to 18.5 ± 0.5 % of DW on day 13. Pulsed electric fields (PEF) and osmotic shock with NaCl (OS) treatments were employed to lyse cells before aqueous LDs extraction. Up to 58 ± 1% of the total lipids were extracted as LDs with OS and up to 42 ± 7% with PEF in the late stationary phase, corresponding to 0.63 ± 0.02 g L-1 and 0.49 ± 0.08 g L-1 lipid concentration in the extracts. The lipid yields increased with cultivation time. LDs size depended on the treatment techniques, with PEF-extracted LDs ranging from 1.4 - 2.0 μm in diameter and OS-extracted LDs from 1.9-2.5 μm in diameter. Furthermore, on average 57% of nitrogenous compounds were co-extracted with OS and 33% with PEF. OS additionally co-extracted chlorophyll. LDs showed no change in size distribution upon 30 days of storage or upon pasteurization. LDs were at least partially charge stabilized, as their zeta potential was influenced by pH. These results suggest that microalgal LDs can be extracted aqueously and could have great potential in the food industry.
Publications 1 - 10 of 35