Anaerobic fungi (AF) possess immense potential for degrading lignocellulosic biomass (LCB) and hold promise for biogas production. They are recognized for playing a major role in the breakdown of crude ingested forage by physical penetration and unique extracellular hemicellulolytic machinery in herbivores gut. Through mixed acid fermentation and presence of hydrogenosome, they engage in crucial symbiotic relationships with methanogens and anaerobic bacteria, ultimately producing methane.
Recognizing their biotechnological potential, the isolation of AF has been attempted across various unexplored habitats. Yet, their isolation techniques have stagnated, constrained by stringent media requirements, thereby limiting their practical application. This study focuses on understanding the growth requirement of AF from rumen and non-rumen habitats by comparing three different culture media. The results demonstrated selective enrichment of certain genera from non-rumen habitats using rumen and depleted rumen fluid media, indicating the manipulation of diversity using rumen fluid medium. Additionally, the use of medium without rumen fluid supported the growth of most genera and harvested the maximum diversity possible.
Another investigation focuses on unexplained challenges of resistance occurred in AF growth over prolonged incubation or in bioaugmentation in anaerobic digesters (ADs). This objective highlighting the impact of various end-products on their proliferation. The results showed the inhibitory effects of ethanol, ammonium, and acetate while revealing resistance to lactate and formate after subculturing, suggesting semi-continuous cultivation as a potential mitigation strategy. For their potential use in ADs, the study explores symbiosis of AF and methanogens, with a special focus on preferred metabolic pathway in AF in presence and absence of methanogen. Metabolic pathway analysis highlighted the involvement of t (PFO) in pyruvate metabolism. Findings emphasized on the preference of malate pathway in hydrogenosome in coculture and pyruvate pathway on monoculture of Cyllamyces.
Finally, the main focus of this study involved in development of rumen simulating anaerobic digestion (RUBICON) system, aimed to enhance AF survival in semicontinuous cultivation. The cultivation system showed successful proliferation of Cyllamyces and Neocallimastix and associated syntrophs, leading to significant reductions in hemicellulose and cellulose. The stable AF consortium exhibited efficient methane production while preventing growth inhibition through regulated retention times.
These investigations collectively shed light on diverse aspects of AF, from their environmental enrichment to growth inhibitors, metabolic pathways, and survival strategies in simulated rumen conditions, providing valuable insights for their biotechnological applications.