Hello,
I am looking for (estimated) degradation rates of cellulose in a classic anaerobic digestion setup (meso or thermophilic, WWTP sludge, 30+ days of operation) to have an idea of the % of cellulose that is actually degraded / converted into biogas and in how much time.
Cellulose is the most abundant organic compound on earth with a chemical formula (C6H10O5)n. Cellulose is a complex carbohydrate consisting of oxygen, carbon, and hydrogen. It is chiral, tasteless and has no odour.The process of cellulose degradation is typically divided into three steps.
1. The long-chain oligosaccharides are cleaved into short-chain oligosaccharides.
2. The short-chain oligosaccharides are degraded to release cellobiose,
3. Hydrolyzed into glucose
Natural biopolymers, such as cellulose, are inherently biodegradable but chemical modification typically required for the obtainment of thermoplastic properties, solubility, or other desired material properties can hinder or even prevent the biodegradation process. Cellulose degradation is carried out primarily by specialist bacteria, with additional contributions from protists and fungi, via a variety of mechanisms. Hemicelluloses are hydrolyzed by cellulolytic bacteria and by generalist, non-cellulolytic microbes, largely via extracellular enzymes. A better understanding of the microorganisms able to convert plant-based feed stocks is needed to improve anaerobic digestion of lignocellulosic biomass. Active thermophilic cellulose-degrading microorganisms are identified from a full-scale anaerobic digester fed with maize by using metagenome-resolved protein stable isotope probing (protein-SIP). Cellulose degradation can occur relatively quickly in an aerobic environment with sufficient moisture, oxygen and suitable temperature (usually between 20°C and 40°C). Under these conditions, cellulose can degrade within months to years
Article Cellulose Degradation in Anaerobic Environments
Hello Maurizio Cuomo ,
The first order degradation rate (k) of cellulose in our high-rate mesophilic AD plants such as on recycled cardboard & paper waste slurries is about 25% per day.
Hope this answers your question.
In a classic anaerobic digestion setup, the degradation rate of cellulose depends on various factors such as temperature, retention time, and sludge composition. However, here are some estimated degradation rates and conversion efficiencies:
- Mesoophilic (30-38°C):
- Degradation rate: 10-20% per day (cellulose to soluble compounds)
- Conversion efficiency: 50-70% (cellulose to biogas)
- Time for 90% degradation: 30-45 days
- Thermophilic (50-55°C):
- Degradation rate: 20-30% per day (cellulose to soluble compounds)
- Conversion efficiency: 70-85% (cellulose to biogas)
- Time for 90% degradation: 20-30 days
Keep in mind that these estimates vary depending on the specific conditions and sludge composition. Some studies report higher or lower degradation rates and efficiencies.
Maurizio Cuomo Anaerobic digestion is what i love and I can answer this by - The degradation rate of cellulose in anaerobic digestion depends on various factors, such as:
1. Type of cellulose material (e.g., agricultural waste, municipal solid waste, or pure cellulose)
2. Particle size and surface area
3. Anaerobic digester design and operating conditions (e.g., temperature, pH, retention time)
4. Microbial community composition and activity
Typically, cellulose degradation rates in anaerobic digestion range from:
- 10-30% per day for easily degradable cellulose (e.g., agricultural waste)
- 5-15% per day for moderately degradable cellulose (e.g., municipal solid waste)
- 1-5% per day for slowly degradable cellulose (e.g., pure cellulose or lignocellulose-rich materials)
The overall degradation rate can be influenced by factors like:
- Hydrolysis rate (breakdown of cellulose into simpler sugars)
- Acidogenesis rate (conversion of sugars into volatile fatty acids)
- Methanogenesis rate (conversion of volatile fatty acids into biogas)
Optimizing these factors can enhance cellulose degradation rates and improve anaerobic digestion efficiency.
Srinivas Kasulla any thoughts on the effect of pH on the conversion of cellulose to methane?
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