Bioconversion of cheese whey permeate into fungal oil by Mucor circinelloides

Abstract

BackgroundOleaginous fungi are efficient tools to convert agricultural waste streams into valuable components. The filamentous fungus Mucor circinelloides was cultivated in whey permeate, a byproduct from cheese production, to produce an oil-rich fungal biomass. Response surface methodology was used to optimize the fermentation conditions such as pH and temperature for increased biomass yield and lipid accumulation. Quantification and characterization of the fungal biomass oil was conducted.ResultsUpstream lactose hydrolysis of the whey permeate increased the biomass yield from 2.4 to 7.8 (g dry biomass/L) compared to that of non-hydrolyzed whey permeate. The combination of low pH (4.5) and pasteurization minimized microbial competition, thus favoring fungal growth. A central composite rotatable design was used to evaluate the effects of temperature (22.4–33.6 °C) and a lower pH range (3.6–4.7) on biomass yield and composition. The highest biomass yield and oil content was observed at high temperature (33.6 °C), while the pH range evaluated had a less pronounced effect. The predictive model was validated at the optimal conditions of 33.6 °C and pH 4.5. The fungal biomass yield plateaued at 9 g dry cell weight per liter, while the oil content and lipid yield reached a maximum of 24% dry biomass and 2.20 g/L, respectively, at 168 h. Triacylglycerides were the major lipid class (92%), which contained predominantly oleic (41%), palmitic (23%), linoleic (11%), and γ-linolenic acid (9%).ConclusionsThis study provided an alternative way of valorization of cheese whey permeate by using it as a substrate for the production of value-added compounds by fungal fermentation. The fatty acid profile indicates the suitability of M. circinelloides oil as a potential feedstock for biofuel production and nutraceutical applications.Electronic supplementary materialThe online version of this article (10.1186/s13036-018-0116-5) contains supplementary material, which is available to authorized users.

Production of filamentous fungal biomass with increased oil content using olive oil as a carbon source

“…Biomass protein content decreased from 48% to 14% with an increase of fat content to up to 34% from 0.3%. Similar results were obtained by Chan et al ., 37 who grew a filamentous fungus ( Mucor circinelloides ) on whey, which produced biomass with 24% oil content and 20% protein content.…”

A novel strategy for triacylglycerides and polyhydroxyalkanoates production using waste lipids

“…The maximum quantity of TAGs accumulated in this study (period IV), was comparable or even higher than the one obtained in previous experiments using both pure (Chan et al, 2018;Lopes et al, 2018) and mixed cultures (Tamis et al, 2015) (Table 4).…”

Mucoromycota fungi as powerful cell factories for modern biorefinery

“…Potato, chicken and pork pulp rest materials were used as carbon and nitrogen source to support growth and lipid production of Mucor circinelloides (Tzimorotas et al 2018). Other examples following the same approach can be found with potato processing wastewater (Muniraj et al 2015), cheese whey permeate (Chan et al 2018), pear pomace (Fakas et al 2009) or wheat sorghum (Economou et al 2010). Rest and waste materials can be also used as lipid source to be transformed into more valued lipids by ex novo lipogenesis.…”