Fermentation and Bioprocess Engineering Processes

Valorization of waste materials into valuable resources through biotechnological methods has received great attention in recent years due to sustainability and environmental concerns. This approach is also compatible with the principles of the circular economy, where waste is seen as a potential raw material for the production of high-value products. The early stages of these approaches usually involve processes such as fermentation and microbial transformation, which offer promising solutions to environmental problems. The term fermentation refers to practices that employ microbial cells as factories to produce value-added products, and the practical application of fermentation goes back as far as the beginnings of human-recorded history; long before cells were even discovered as units of life!

However, microbial bioprocesses are still sometimes considered modern inventions since the advanced biomanufacturing industry is now utilizing recombinant technologies that emerged in the 80s and the bioreactor designs in large-scale stainless-steel vessels that came about shortly before that. Today, after only a few decades, microbial fermentation has become the foundation of a thriving biotech industry with production at an impressive large scale.

Many food or agricultural wastes are converted into biogas through anaerobic digestion. Similarly, syngas fermentation utilizes microbial electrocatalysts to convert gasified biomass into alcohols. Thus, a suitable alternative path for sustainable biofuel production emerges. It is part of a growing trend to utilize microbial fermentation to recycle waste substrates, such as fatty acids from wastewater and organic residues in mushroom cultivation, into useful products.

Additionally, the production of bioactive compounds such as polysaccharides, menaquinone-7, and natural flavors through microbial fermentation shows that fermentation technology can be used in many areas. This method offers environmentally friendly production routes that support the food, pharmaceutical, and cosmetic industries. Techniques such as thermophilic anaerobic fermentation and online fermentation optimization reflect advances in bioprocess efficiency by adapting fermentation conditions in real time to accommodate industrial scale-up.

This Special Issue has, therefore, been undertaken to provide some updates in this area. As a result, several novel approaches and cutting-edge research are featured, all at the frontiers of different sectors of biotech and employing microbial fermentation.

• Across Agricultural Biotech (Green Biotechnology), studies here have investigated physicochemical methods to improve efficiency of anaerobic digestors employed for food waste valorization and the production of biofertilizers. Other researchers looked into wastewater valorization of mushroom cultures to enhance lipid fermentation in yeast. Complementing their efforts, another study illustrated the benefits of pretreating brewers’ spent grain to improve volatile fatty acid production through thermophilic anaerobic fermentation [1,2,3].
• Looking into Industrial Biotech (White Biotechnology), our colleagues characterized novel acetogens to produce C2–C6 alcohols from syngas [4,5].
• In Food Biotech (Yellow Biotechnology), the research teams produced and characterized Kombucha tea from different sources of tea and were able to model kinetics of its production [6,7,8].
• As an effort in Nutraceuticals Biotech (Orange Biotechnology), fermentation of Menaquinone-7 (vitamin K2) was reviewed and the influence of environmental factors and storage conditions on the isomer profile was highlighted [9,10].
• And finally, in Pharma Biotech (Red Biotechnology) researchers screened Bacillus strains to ferment Dendrobium officinale into polysaccharides and, furthermore, investigate these polysaccharides for skincare applications [11,12].

This convergence of waste utilization and microbial synthesis demonstrates the potential for innovation in the field of biotechnology that promotes resource efficiency and environmental sustainability. Through optimized fermentation strategies and bioprocessing technologies, the aim is to facilitate the creation of value-added products, increase economic sustainability and reduce our ecological footprint. Ongoing research and development in these areas holds the promise of transforming industries by increasing resilience in the face of global sustainability challenges.