A design collection celebrating the microscopic universe in the dust beneath our feet, acknowledging some of the most significant microbial players in the ecology of decomposition through the aesthetic of cosmic wonder.
This initial collection consists of 6 bacteria that have been chosen for their significance in the composting process and soil health, but also their relevance to human health and cultural interest. They have been organized based on the phase of the hot composting process where they are most prominent, acknowledged mostly based on genus. I painted them based on electron microscopy images of representative species of each bacteria genus.
The designs are available as greeting cards, posters, art prints, notebooks, and stickers through RedBubble. Show your favorite earth loving, fermenting, microbe appreciating friend how much you appreciate them. Write them a love letter of micro-cosmic delight. Collect all 6 bacteria for a complete compost ecological successional experience!
Stage 1. Mesophilic Initiation:
Lactobacillus + Leuconostoc
The initial mesophilic phase consists of a mix of decomposers and fermenters, as much of the fresh feedstock material is fermenting when it enters the pile. Bacteria like Lactobacillus and Leuconostoc are best known for their role in fermentation communities, and the production of foods like yogurt, kefir, and kombucha. Even though fermentation is an anaerobic process, these guys are aerotolerant, and can still do their thing in the presence of oxygen.
Stage 2. Thermophilic Activation:
Bacillus + Actinobacteria (Streptosporangium)
The appropriate pile conditions increases microbial activity, raising the internal temperature of the pile until it shifts into the 2nd phase where it reaches peak thermophilic temperature and stays there for a few weeks. Bacillus species and Actinobacteria (phylum) are the dominant bacteria at this time. I chose Streptosporangium as the sample species for Actinobacteria, which is the name of a phylum.
Stage 3. Cooldown + Maturation:
Pseudomonas + Enterobacter
As the original organic waste material breaks down and humus (the dark chocolate end material, the end product of decomposition) begins to form, the microbial activity slows down and the temperature begins to cool, entering the 3rd phase. At this time, the microbial ecology shifts its focus to lignin breakdown and humus formation. Ultimately, the compost is finished when the temperature has reached ambient and the microbial activity has calmed down and stabilized to regular rates. Pseudomonas and Enterobacter are often detected in mature compost.
Greeting Cards + Postcards:
Art Prints + Collectibles:
Hot Composting + Succession of Microbial Ecology
In the hot composting method, the pile is built according to a hot compost recipe with specific parameters around C:N or brown:green ratio, moisture content, and airflow. The decomposition process is initiated once the pile is built – microbes begin to break down and metabolize the organic matter into plant available nutrients and long-term organic matter storage like humus.
There is a phenomenon in ecology known as succession, where a community of organisms in an ecosystem co-evolve in species composition and diversity as the ecosystem matures and stabilizes. The same thing happens during hot composting – the composition of micro-organisms active and present in the pile changes during the composting process, much like ecological succession. In this sense, the bacteria that are part of this series reflect the phases of ecological succession happening during the hot composting process.
Stage 1: Mesophilic Initiation
Fresh feedstock materials combine to initiate the thermophilic decomposition process. Much of the food waste is fermenting when it enters the pile. It is the compounds that are easily degraded that are the first to be metabolized, such as simple sugars, starches, and lipids. After a few days, the frenzy of microbial metabolic activity releases heat and the temperature begins to increase.
Organisms like Lactobacillus and Leuconostoc are often found during this mesophilic initiation phase, which are part of fermentation communities, involved in the production of sauerkraut, cheese, kefir, kombucha, and even the anaerobic composting method bokashi.
Stage 2: Thermophilic Activation
The thermophilic phase is marked by temperatures in the range of 120 – 160ºF. Reaching temperatures higher than 160ºF may be harmful as survival structures for beneficial organisms may be destroyed, and increasing temperatures increase the potential for starting a fire.
At this time, proteins and lignocellulosic substrates are being actively decomposed. Plant cell walls and woody materials consist of lignin, cellulose, and hemicellulose. Lignin degradation is important for humus formation.
Bacillus spp and Actinobacteria such as Streptosporangium and Streptomyces dominate during the thermophilic phase. Actinobacteria are visible as white ashy material in hot parts of the pile, especially on high carbon woody materials.
Stage 3: Cooldown + Maturation
Most of the original organic matter has been broken down and the compost is primarily engaged in lignocellulose degradation and humus formation. Microbial activity slows down and the temperature begins to cool.
Mesophilic organisms begin to recolonize the pile. Pseudomonas has been consistently detected in mature composts, as well as Enterobacter.
I’ll be sharing an article about each bacteria over the next 6 weeks. Stay tuned for the first article on Lactobacillus!