Optimization of Citrus Pulp Waste-Based Medium for Improved Bacterial Nanocellulose Production

Area of Science:

• Biotechnology
• Materials Science
• Sustainable Chemistry

Background:

• Bacterial nanocellulose (BC) exhibits unique properties, driving demand across various applications.
• Sustainable production of BC is crucial, with increasing focus on utilizing waste biomass.
• Citrus pulp waste (CPW) presents a promising, underutilized resource for biogenesis.

Purpose of the Study:

• To optimize a citrus pulp waste (CPW) medium for enhanced bacterial nanocellulose (BC) production using *Komagataeibacter sucrofermentans*.
• To investigate sustainable alternatives for BC production, reducing reliance on conventional media components.
• To characterize the properties of BC produced from the optimized CPW medium.

Main Methods:

• Plackett-Burman design screened key medium parameters (pH, yeast extract, CPW sugar, inoculum).
• Response surface methodology (central composite design) optimized significant factors: CPW sugars and yeast extract.
• Material characterization assessed BC thermal stability and crystallinity.
• Spent baker's yeast hydrolysate (BYH) evaluated as a sustainable yeast extract substitute.

Main Results:

• Optimized CPW medium yielded 66.7 ± 5.1 mgDW/gCPW, a 14-fold increase over unoptimized conditions (4.3 ± 0.4 mgBC/gCPW).
• Produced BC demonstrated high thermal stability (71% crystallinity, 30% mass retained at 600 °C).
• Using spent baker's yeast hydrolysate achieved a BC titer of 9.3 ± 0.6 g/L, enhancing process sustainability.

Conclusions:

• Citrus pulp waste is an effective substrate for high-yield bacterial nanocellulose production.
• Optimization significantly enhances BC yield, demonstrating the potential of waste valorization.
• Spent baker's yeast hydrolysate offers a sustainable alternative to yeast extract in BC biogenesis.