Low-pressure airlift fermenter for single cell protein production: II. Continuous culture of pichia yeast

Direct nitrogen stripping and upcycling from anaerobic digestate during conversion of cheese whey into single cell protein

The environmental impact of the dairy industry is heavily influenced by the overproduction of nitrogen- and carbon-rich effluents. The present study proposes an innovative process to recover waste contaminated nitrogen from anaerobic digestate while treating excess cheese whey (CW) and producing high-quality, clean single cell protein (SCP). By relying on direct aeration stripping techniques, employing an airflow subsequently used in the aerobic cheese whey fermentation step, the investigated process was able to strip 41-80% of the total ammonium nitrogen (N-NH₄⁺) from liquid digestate. The stripped ammonia gas (NH₃) was completely recovered as N-NH₄⁺ in the acidic CW, and further upcycled into SCP having a total protein content of 74.7% and a balanced amino acids profile. A preliminary techno-economic analysis revealed the potential to directly recover and upcycle nitrogen into SCP at costs (4.3-6.3 €·kgN^-1) and energetic inputs (90-132 MJ·kgN^-1) matching those of conventional feed and nitrogen management processes.

Biotechnological Interventions for Ginsenosides Production

Ginsenosides are secondary metabolites that belong to the triterpenoid or saponin group. These occupy a unique place in the pharmaceutical sector, associated with the manufacturing of medicines and dietary supplements. These valuable secondary metabolites are predominantly used for the treatment of nervous and cardiac ailments. The conventional approaches for ginsenoside extraction are time-consuming and not feasible, and thus it has paved the way for the development of various biotechnological approaches, which would ameliorate the production and extraction process. This review delineates the biotechnological tools, such as conventional tissue culture, cell suspension culture, protoplast culture, polyploidy, in vitro mutagenesis, hairy root culture, that have been largely implemented for the enhanced production of ginsenosides. The use of bioreactors to scale up ginsenoside yield is also presented. The main aim of this review is to address the unexplored aspects and limitations of these biotechnological tools, so that a platform for the utilization of novel approaches can be established to further increase the production of ginsenosides in the near future.