Article
Microbiology
Tan Liu, Zhihui Chen, Yunhua Xiao, Mingmin Yuan, Chenkai Zhou, Gang Liu, Jun Fang, Bo Yang
Summary: Nitrogen limitation and starvation can increase the lipid content of microalgal cells but decrease biomass productivity, pigment concentration, and protein content. Three-day nitrogen starvation is a suitable strategy to produce lipid-rich biomass and causes changes in cell morphology. Saturated fatty acids dominate, making microalgae a potential feedstock for biodiesel production.
Article
Energy & Fuels
S. M. Zakir Hossain, N. Sultana, M. M. Hossain, S. A. Razzak
Summary: This study investigated the effects of light-dark cycles and NaNO3 dose on Chlorella kessleri microalgal-specific growth rate, biomass productivity, and intracellular lipid productivity. The results of single-objective and multi-response optimization showed the maximum achievable values and the optimal culture conditions for the production of lipid from microalgae. The use of central composite design with desirability function was proven to be useful in designing and operating photobioreactors.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Biochemistry & Molecular Biology
Shengquan Huang, Xiuyu Zhang, Zongwen Song, Mati Ur Rahman, Ben Fan
Summary: The research on plant endophytes, particularly Pantoea eucalypti FBS135, has been the focus of attention due to its plant growth-promoting activity and ability to grow under low nitrogen conditions. This study examined the transcriptome of FBS135 under nitrogen deficiency and found that it actively regulates its gene expression in response to nitrogen limitation. The downregulated genes were enriched in ribosome pathway-related genes, while transportation-associated and nitrogen metabolism-related genes were significantly upregulated. Additionally, four genes involved in low-nitrogen tolerance were identified through a transposon library. These findings provide insights into the mechanisms of endophytes in adapting to nitrogen-limited environments and lay the foundation for further investigation.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Environmental Sciences
Nathan S. Garcia, David Talmy, Wei-Wei Fu, Alyse A. Larkin, Jenna Lee, Adam C. Martiny
Summary: Environmentally driven variability in ocean plankton elemental stoichiometry plays a key role in biogeochemical processes. This study investigates the diel variability in C:N of ocean particles and finds temperature to be the strongest predictor. Predictions show that future rising temperatures will lead to increased C:N variability.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Review
Thermodynamics
Kuan Shiong Khoo, Imran Ahmad, Kit Wayne Chew, Koji Iwamoto, Amit Bhatnagar, Pau Loke Show
Summary: Microalgae has attracted attention as an alternative feedstock for biofuel production, especially when combined with genetic modification strategies for enhanced lipid productivity. As a potential sustainable energy source, microalgae utilize solar energy and carbon dioxide to produce energy-rich compounds that can be further converted into various types of biofuels. Biodiesel from transesterification of triacylglycerols is considered the most sustainable replacement for fossil-based diesel fuel. However, challenges in productivity, production cost, and upscaling technology hinder the commercialization of microalgae-based biofuel. This review article provides an overview of microalgae classification, factors affecting growth during cultivation, upstream processing, downstream processing, genetic modification strategies, and discusses the current challenges and future prospects of microalgae-based biofuels, including sustainability, industry status, and risks and legislation considerations.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Multidisciplinary Sciences
T. K. Westberry, M. J. Behrenfeld, Y. R. Shi, H. Yu, L. A. Remer, H. Bian
Summary: By using global satellite ocean color products, this study demonstrates that atmospheric dust deposition plays a significant role in providing vital nutrients for phytoplankton growth in the surface layer of the ocean. The responses to dust deposition vary regionally, with some areas experiencing substantial changes in phytoplankton biomass, while in other areas, the response is reflected in a change in physiological status or health. Climate-driven changes in atmospheric aerosols will alter the relative importance of this nutrient source.
Article
Microbiology
Julien Boehm, Karsten Kauss, Klaudia Michl, Lisa Engelhardt, Eva-Maria Brouwer, Martin Hagemann
Summary: Future sustainable energy production can be achieved by cultivating photoautotrophic microorganisms, such as cyanobacteria, to synthesize valuable products directly from CO2 and sunlight. This study demonstrates that carbon flux towards pyruvate is a bottleneck for high ethanol production in cyanobacteria, and the mutation of the pirC gene can increase carbon partitioning towards lower glycolysis, resulting in improved ethanol production under nitrogen depletion. The findings highlight the importance of understanding regulatory mechanisms involved in cyanobacterial carbon partitioning for engineering more productive strains.
FRONTIERS IN MICROBIOLOGY
(2023)
Review
Marine & Freshwater Biology
Ingrid Chorus, Elly Spijkerman
Summary: Reynolds elegantly synthesized the impact of limitation and co-limitation on phytoplankton communities, emphasizing that reducing P concentration is sufficient to mitigate eutrophication, but increasing N concentration may also be beneficial in certain circumstances. Research on stoichiometry and co-limitation serves to enhance our understanding of phytoplankton ecophysiology and community ecology.
Article
Plant Sciences
Xingkang Li, Yuanmei Liang, Kai Li, Peng Jin, Jie Tang, Anna Klepacz-Smolka, Stanislaw Ledakowicz, Maurycy Daroch
Summary: The study showed that both low temperature and nitrogen starvation resulted in decreased pigment content in the thermophilic cyanobacterium strain Thermosynechococcus E542, but had different effects on the OJIP curves. The combined treatment led to the lowest pigment content.
Article
Plant Sciences
Misao Shimojo, Masashi Nakamura, Ginga Kitaura, Yuta Ihara, Shinsuke Shimizu, Koichi Hori, Masako Iwai, Hiroyuki Ohta, Kimitsune Ishizaki, Mie Shimojima
Summary: This study analyzed the impact of membrane lipid remodeling on inorganic phosphate uptake and discovered the crucial role of MpPAH in the growth of Marchantia polymorpha. The mutation of MpPAH affects plant growth by suppressing the synthesis of plastid glycolipids through the endoplasmic reticulum pathway.
Article
Multidisciplinary Sciences
Siyuan Wang, Coco Koedooder, Futing Zhang, Nivi Kessler, Meri Eichner, Dalin Shi, Yeala Shaked
Summary: Trichodesmium utilizes multiple pathways to acquire nutrients, and recent studies have shown its ability to selectively collect iron-rich and phosphorus-coated minerals, optimizing its nutrient utilization. This unique capability contributes to Trichodesmium's ecological success and potential adaptation to future warmer oceans.
Article
Biotechnology & Applied Microbiology
Liufu Wang, Di Ming, Yingying pan, Liqiu Shi, Wenzhi Wei
Summary: The main aim of this study is to investigate the effects of combined nitrogen limitation and hydrogen peroxide treatment on lipid accumulation in Chlorella sorokiniana. In addition, the relationships between reactive oxygen species (ROS), Ca2+ and lipogenic genes were analyzed to study the regulative networks involved in lipid accumulation. The results showed that lipid content and levels of endogenous ROS, Ca2+ increased under nitrogen limitation with H2O2 added, and ROS level could affect lipid accumulation through lipogenic gene expression. The study provides an effective strategy to improve lipid accumulation in C. sorokiniana and offers evidence of the involvement of ROS, Ca2+ and lipogenic genes in lipid biosynthesis in microalgae under combined treatment.
ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS
(2023)
Article
Engineering, Environmental
S. Morales-Palomo, C. Gonzalez-Fernandez, E. Tomas-Pejo
Summary: Microbial lipids can be produced from volatile fatty acids (VFAs) derived from organic wastes, and the lipid yields can be comparable to or even higher than those from sugars. The optimal culture conditions for lipid production were determined by adjusting VFAs concentrations, acids profiles, and carbon:nitrogen (C:N) ratios. This study highlights the suitability of using VFAs from wastes as low-cost carbon sources for lipid production in Yarrowia lipolytica.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Biotechnology & Applied Microbiology
Paul Chambonniere, Adriana Ramirez-Romero, Alexandra Dimitriades-Lemaire, Jean-Francois Sassi, Florian Delrue
Summary: This study monitored the physiological changes of Chlorella vulgaris NIES 227 during lipid accumulation under nutrient limitation and found that the growth capacity of the microalgae can be preserved during the exponential growth phase, but under nutrient limitation, protein content decreases while lipid content increases, and the photosynthetic activity decreases. These findings are important for optimizing industrial processes in microalgae biofuel production.
FERMENTATION-BASEL
(2022)
Article
Energy & Fuels
Sungwhan Kim, Minsik Kim, Yong Keun Chang, Donghyun Kim
Summary: The effects of different nutrient starvation strategies on lipid production in Ettlia sp. YC001 attached cultivation were investigated. A detailed study on compositional variation over the depth of biofilms was conducted to understand the phenomena within the biofilms under various nutrient conditions. The results showed that nutrient starvation increased the lipid content of biofilms by 3-7%, but significantly limited biomass growth.
Article
Optics
Olivier Bernard, Yves Bellouard
Summary: The use of femtosecond lasers provides a versatile method for encoding information and modifying transparent materials with sub-micron resolution, thanks to the non-linear nature of laser-matter interaction. However, achieving repeatable and accurate results relies heavily on time-consuming machine-specific calibration and experiment-specific fine-tuning due to the complex physical processes involved.
JOURNAL OF PHYSICS-PHOTONICS
(2021)
Article
Automation & Control Systems
Walid Djema, Laetitia Giraldi, Sofya Maslovskaya, Olivier Bernard
Summary: The paper focuses on a generic optimal control problem derived from competition between two microbial populations, characterizing the optimal control strategy using Pontryagin's Maximum Principle and providing conditions for the existence of a turnpike property. Illustrative results are shown on microalgae using numerical methods.
Article
Mathematics, Applied
Agustin G. Yabo, Jean-Baptiste Caillau, Jean-Luc Gouze, Hidde de Jong, Francis Mairet
Summary: Gaining a better understanding of microbial growth is crucial for scientific research, and self-replicator models based on resource allocation principles have been effective in explaining experimental observations. This study extends a previous model by considering the role of proteins in basic functions and investigates their impact on optimal resource allocation strategies in response to environmental changes. The analysis reveals a globally attractive equilibrium and complex solutions, providing a generalized perspective on microbial growth analysis.
SIAM JOURNAL ON APPLIED DYNAMICAL SYSTEMS
(2022)
Article
Plant Sciences
Anne Pajot, Johann Lavaud, Gregory Carrier, Matthieu Garnier, Bruno Saint-Jean, Noemie Rabilloud, Caroline Baroukh, Jean-Baptiste Berard, Olivier Bernard, Luc Marchal, Elodie Nicolau
Summary: Differences in lhc classification in Chromista were observed. A classification of the lhcf family with specific groups for haptophytes, diatoms, and seaweeds was proposed. Similarity analysis was performed to identify and characterize Fucoxanthin and Chlorophyll a/c-binding Protein (FCP) in the haptophyte microalgae Tisochrysis lutea. The study revealed dynamic changes in lhc gene expression with nitrogen depletion and the exclusive nighttime expression of the lhcx2 gene in T. lutea, suggesting its role in protecting cells from light exposure after prolonged darkness.
FRONTIERS IN PLANT SCIENCE
(2022)
Article
Automation & Control Systems
Olivier Bernard, Liu-Di Lu, Julien Salomon
Summary: In this article, the authors investigate a periodic resource allocation problem in a dynamical system, which is applied to a biological system. The goal is to find optimal control strategies to optimize the cost or benefit of the system. The authors illustrate this problem using an industrial biological application and introduce a nonlinear optimization problem and a suboptimal solution to overcome the computational difficulty. Numerical experiments are performed to assess the benefits of optimal strategies in different settings.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2023)
Article
Biochemical Research Methods
Bastien Polizzi, Andrea Fanesi, Filipa Lopes, Magali Ribot, Olivier Bernard
Summary: This article presents a spatial model for the growth of a photosynthetic microalgae biofilm and investigates the biofilm's structural dynamics and the impact of optimal harvesting strategies on its structure.
PLOS COMPUTATIONAL BIOLOGY
(2022)
Article
Engineering, Chemical
Walid Djema, Terence Bayen, Olivier Bernard
Summary: This paper investigates the problem of species separation in minimal time. The evolution of two competing microorganism populations for the same resource is described using the Droop model. The paper focuses on solving an optimal control problem subject to a controlled system with five dimensions. The objective is to select the desired species in minimal time and synthesize an optimal feedback control. The paper provides properties of optimal controls and utilizes the Pontryagin Maximum Principle and a study of singular arcs for analysis. The theoretical results are validated using numerical examples with microalgae and a direct method in optimal control.
Article
Biotechnology & Applied Microbiology
Andrea Fanesi, Thierry Martin, Cyril Breton, Olivier Bernard, Romain Briandet, Filipa Lopes
Summary: Microalgae biofilms have ecological importance and biotechnological potential. However, a comprehensive understanding of their structure and physiology is still lacking. In this study, a novel approach was developed to nondestructively characterize the physiological and structural information of microalgae biofilms. The results showed that the physiology of cells in complex biofilms is more affected, likely due to alterations in local environmental conditions.
BIOTECHNOLOGY AND BIOENGINEERING
(2022)
Article
Microbiology
Francesca Casagli, Olivier Bernard
Summary: High-rate algal-bacterial ponds (HRABP) are considered as an interesting solution to reduce energy demand in wastewater treatment, yet the efficiency is highly influenced by solar fluxes and temperature fluctuations. The temperature patterns and reactor configurations play a crucial role in the biological process of HRABPs.
Article
Automation & Control Systems
Frederic Mazenc, Olivier Bernard
Summary: This article presents a simple, necessary, and sufficient condition for a real matrix to be similar to a Metzler matrix of dimension three, and provides a construction method for the transfer matrix. This construction is utilized to design an interval observer for a family of continuous-time systems. The case of limit cycles in the love dynamics is used as an example for the interval observer design.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Green & Sustainable Science & Technology
Francesca Casagli, Olivier Bernard
Summary: Existing mathematical models for outdoor biotechnological processes cannot predict the future dynamics, thus fully predictive models are needed. The FLAME modelling framework integrates biological, heat transfer, and chemical sub-models to forecast outdoor bioprocesses. It provides a powerful tool for controlling and optimizing environmental processes.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Biotechnology & Applied Microbiology
David Morgado, Andrea Fanesi, Thierry Martin, Sihem Tebbani, Olivier Bernard, Filipa Lopes
Summary: This study utilized a rotating system to produce the high-value compound astaxanthin using Haematococcus pluvialis biofilms. The effect of nitrogen regime, light intensity, and light history on biofilm traits was assessed, showing that H. pluvialis biofilms follow the classical growth stages of bacterial biofilms and that training the biofilms during the green stage can significantly enhance astaxanthin productivity.
BIOTECHNOLOGY AND BIOENGINEERING
(2023)
Proceedings Paper
Automation & Control Systems
Olivier Bernard, Liu-Di Lu, Julien Salomon
Summary: This paper focuses on optimizing the growth of microalgae in raceway ponds by exploring mixing strategies and designing the shape of the bottom topographies. A physical-biological coupled model is used to describe the growth of the algae, along with considering a simple model of a mixing device like a paddle wheel. The results suggest that specific mixing strategies and non-trivial topographies can enhance microalgal productivity in raceway ponds.
Proceedings Paper
Automation & Control Systems
Carlos Martinez, Bruno Assis Pessi, Olivier Bernard
Summary: This paper examines the dynamics and productivity of biomass in a continuous microalgae culture contaminated by predators. The study presents a model outlining the system where photolimited microalgae are grazed by zooplankton, discussing conditions for coexistence equilibrium and the behavior of microalgae and predators in different scenarios. Numerical simulations demonstrate that operating the system at an optimal dilution rate can lead to the extinction of predators.
Letter
Gastroenterology & Hepatology
Giuseppe Maggiore, Andrea Pietrobattista, Daniela Liccardo, Marco Sciveres, Silvia Nastasio, Emmanuel Jacquemin, Olivier Bernard
JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION
(2021)
