How Bacteria That Boost Algae Growth Adapt to Biogas Conditions

Greg Howard
18th March, 2024

How Bacteria That Boost Algae Growth Adapt to Biogas Conditions

Image Source: Natural Science News, 2024

Key Findings

  • In a synthetic biogas environment, the bacterium A. brasilense adapts by changing the activity of 394 genes
  • Some genes increased activity boosts microalgae growth, aiding renewable energy production from biogas
  • The study suggests A. brasilense could be key in converting biogas to clean energy through microalgae
Understanding how to efficiently convert biogas into renewable energy is a significant challenge in the field of environmental biotechnology. A promising approach to this challenge involves utilizing microalgae, tiny photosynthetic organisms, along with beneficial bacteria that can enhance their growth and metabolism. A recent study[1] carried out by researchers at the Center for Biological Research of the Northwest (CIBNOR) has shed light on how a specific bacterium, Azospirillum brasilense, adapts and thrives in an atmosphere of synthetic biogas, which is rich in methane and carbon dioxide. Biogas, a mixture of gases produced by the breakdown of organic matter in the absence of oxygen, primarily consists of methane and carbon dioxide. It's a potential source of clean energy, but its high methane content poses a challenge for microbial processes that could convert it into more useful forms. The CIBNOR study focused on how the bacterium A. brasilense, known for promoting the growth of microalgae, responds at the genetic level to a synthetic biogas environment. The researchers used a technique called microarray-based transcriptome analysis to observe changes in the bacterium's gene expression when exposed to biogas. They discovered 394 differentially expressed genes (DEGs), which are genes that show a significant change in expression due to the biogas atmosphere. Some genes were more active (upregulated) and others less (downregulated), indicating a complex response to the biogas environment. One key finding was the upregulation of genes related to the production of indole-3-acetic acid (IAA), a molecule that promotes plant and microalgal growth[2]. This is consistent with previous studies showing that A. brasilense can enhance the CO2 fixation rate of microalgae like Chlorella vulgaris and Scenedesmus obliquus, which is a crucial step in converting CO2 into biomass[2][3]. Additionally, genes involved in the production of riboflavin (vitamin B2) and polyhydroxybutyrate (PHB), a biodegradable plastic, were also upregulated. Interestingly, the study noted the activation of genes associated with a bacterial mechanism known as the Type VI secretion system (T6SS). This system is used by bacteria to interact with other cells and can help A. brasilense attach to microalgae, thereby boosting their metabolic performance[4]. This attachment is vital for enhancing lipid, carbohydrate, and pigment production in microalgae, which are essential components for biofuel production and other biotechnological applications. The findings of the CIBNOR study are significant for several reasons. First, they demonstrate that A. brasilense can adapt to a biogas atmosphere, which is crucial for using this bacterium in biotechnological processes involving microalgae. Second, the study provides insights into the genetic changes that occur in A. brasilense, which could lead to improved strategies for biogas upgrading or conversion into renewable energy. Moreover, the compatibility of A. brasilense with various environmental conditions and its ability to promote plant and microalgal growth make it a versatile tool in both agriculture and environmental biotechnology. While pesticides can impact the effectiveness of A. brasilense as a crop inoculant[5], the bacterium's resilience and growth-promoting abilities under biogas conditions suggest that it can be a valuable asset in sustainable agricultural and energy production systems. In conclusion, the research from CIBNOR advances our understanding of how beneficial bacteria like A. brasilense can be harnessed to improve the efficiency of microalgal metabolism in the production of renewable energy from biogas. By revealing the bacterium's ability to adapt its gene expression in response to a biogas environment, this study paves the way for innovative biotechnological applications that could have a significant impact on clean energy production and environmental sustainability.



Main Study

1) Metabolic and physiological adaptations of microalgal growth-promoting bacterium Azospirillum brasilense growing under biogas atmosphere: a microarray-based transcriptome analysis.

Published 16th March, 2024

Related Studies

2) Active indole-3-acetic acid biosynthesis by the bacterium Azospirillum brasilense cultured under a biogas atmosphere enables its beneficial association with microalgae.

3) Synergic association of the consortium Arthrospira maxima with the microalga growth-promoting bacterium Azospirillum cultured under the stressful biogas composition.

4) The Azospirillum brasilense type VI secretion system promotes cell aggregation, biocontrol protection against phytopathogens and attachment to the microalgae Chlorella sorokiniana.

5) Impact of seed-applied fungicide and insecticide on Azospirillum brasilense survival and wheat growth-promoting ability.

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