Biodiesel production from microbial granules in sequencing batch reactor.

Area of Science:

• Biotechnology
• Environmental Science
• Chemical Engineering

Background:

• Biodiesel production from microbial biomass is a sustainable alternative to fossil fuels.
• Granular sludge and consortia offer unique microbial communities for bioprocesses.
• Optimizing in situ transesterification is crucial for efficient biodiesel generation.

Purpose of the Study:

• To investigate the effect of reaction variables on in situ transesterification for biodiesel production.
• To compare biodiesel yield and characteristics from aerobic granular sludge (AG) and algae-bacteria granular consortia (AAG).
• To understand the microbial community's role in biodiesel composition.

Main Methods:

• In situ transesterification optimization using varying methanol quantity, catalyst concentration, and reaction time.
• Characterization of biodiesel properties and composition.
• Microbial community analysis using 16S rRNA sequencing.

Main Results:

• Biodiesel yield was most influenced by methanol quantity, followed by catalyst concentration and reaction time.
• Algae-bacteria granular consortia (AAG) achieved a maximum yield of 66.21 mg/g SS, significantly higher than aerobic granular sludge (AG) at 35.44 mg/g SS.
• AAG biodiesel contained a higher percentage of poly-unsaturated fatty acids (21.86%) compared to AG (1.2%), attributed to Scenedesmus addition. Xanthomonadaceae and Rhodobacteraceae were dominant in AG and AAG, respectively.

Conclusions:

• Reaction variable optimization significantly impacts biodiesel yield but not its fundamental properties.
• Algae-bacteria granular consortia (AAG) demonstrate superior potential for biodiesel production compared to AG.
• Microbial community composition plays a critical role in determining the fatty acid profile of the produced biodiesel.