The Streptomycetes are a genus of gram-positive soil bacteria known for their ability to produce antibiotics. These filamentously growing bacteria show a similar life cycle as fungi and are known to produce a lot of different enzymes during their stages of growth [1].
Pseudomonas putida is a gram-negative soil bacteria. Some strains are known to be tolerant towards stressful environments such as high concentrations of organic solvents [2].
E. coli is one of the work horses considering molecular work. They are relatively easy to engineer and are mainly used as plasmid vehicles during cloning and enzyme production [3].
Aspergillus niger is a filamentous fungi known to cause the molding of onions. Apart from this Aspergillus niger is an important biotechnological organism since it is able to degrade a variety of natural polymers [4].
Picture 1: Streptomyces pellet, made by Jo-Anne Verschoor 100x enlarged Leiden 2021.
Picture 2: Pseudomonas putida (Trevisan 1889) Migula 1895 - Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Germany - CC BY-SA. https://www.europeana.eu/nl/item/11637/PROKARYAXDSMZXGERMANYXDSMX26252
Picture 3: E.coli on agar. SEM door David Gregory & Debbie Marshall - Wellcome Collection, United Kingdom - CC BY.
https://www.europeana.eu/nl/item/9200579/y3w38jks
Picture 4: Aspergillus niger growth on agar plate. https://www.universiteitleiden.nl/en/research/research-projects/science/ibl-improving-the-filamentous-fungus-aspergillus-niger-as-cell-factory-for-starch-degrading-enzymes.
1: Urem et al, 2016 https://onlinelibrary.wiley.com/doi/full/10.1111/mmi.13464
2: Kusumawardhani et al, 2018 https://www.sciencedirect.com/science/article/pii/S0167779918301203?via%3Dihub
3: Pines et al, 1999 https://link.springer.com/article/10.1385/MB:12:1:25
4: https://www.universiteitleiden.nl/en/research/research-projects/science/ibl-improving-the-filamentous-fungus-aspergillus-niger-as-cell-factory-for-starch-degrading-enzymes.