Shift in methanogenic community in protein degradation using different inocula

Area of Science:

• Environmental Science
• Biotechnology
• Microbiology

Background:

• Anaerobic digestion (AD) of protein-rich wastes poses challenges due to ammonia and hydrogen sulfide production.
• Effective treatment requires careful selection of microbial communities for optimal performance.

Purpose of the Study:

• To evaluate the impact of different inocula on the anaerobic digestion of gelatin and gluten.
• To identify key microbial populations influencing methane production from proteinaceous substrates.

Main Methods:

• Batch anaerobic digestion experiments using eight distinct inocula.
• Substrates included gelatin and gluten at a controlled organic loading rate.
• Methane production data analyzed using the modified Gompertz model.
• Microbial community structure assessed via 16S rRNA gene sequencing.

Main Results:

• Significant variation in maximum methane production rates (up to threefold difference) observed for both gelatin and gluten.
• Dominance of Methanoculleus in inocula from food waste-treating plants.
• Dominance of Methanosaeta in inocula from other types of waste-treating plants.
• Rates for gelatin: 2.734-7.438 mLCH4 gCOD-1 d-1; for gluten: 1.950-5.532 mLCH4 gCOD-1 d-1.

Conclusions:

• Inoculum source critically influences the efficiency of anaerobic digestion for proteinaceous waste.
• Microbial composition, particularly the dominance of specific methanogens, is key to successful AD.
• Appropriate inoculum selection is essential for optimizing methane yield from gelatin and gluten.