Aerobic and anaerobic ethanol production by Mucor circinelloides during submerged growth

Abstract

The dimorphic organism Mucor circinelloides is currently being investigated as a potential host for heterologous protein production. The production of ethanol on pentose and hexose sugars was studied in submerged batch cultivations to further the general knowledge of Mucor physiology, with a view to the minimisation or elimination of the by-product ethanol for future process design. Large amounts of ethanol were produced during aerobic growth on glucose under non-oxygen limiting conditions, which is indicative of M. circinelloides being a Crabtree-positive organism. Ethanol production on galactose or xylose was less significant. The response of the organism to increased ethanol concentrations, both as the sole carbon source and in the presence of a sugar, was investigated in terms of biomass formation and morphology.

Antifungal activity of rhamnolipids against dimorphic fungi

“…The observed dimorphic properties of the isolated fungus (Fig. 1) further confirmed M. circinelloides, which is characterized by dimorphic growth (Lubbehusen et al, 2004), similar to other Mucor species such as M. racemosus, M. rouxii and M. genevensis (Orlowski, 1991).…”

Rapid and Effective Oxidative Pretreatment of Woody Biomass at Mild Reaction Conditions and Low Oxidant Loadings

“…Microplate (96-well; Sarstedt, Germany) layout for three-tier screening. Fusarium oxysporum wild-type strain 11C (WT) and putative transformants were inoculated into columns (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and screened across five treatments: T1; no ethanol, T2; hygryomcinB (60 μg ml -1 ; Sigma, UK), T3; 0.5% (vv -1 ) ethanol (ethyl alcohol; Sigma, UK), T4; 6% (vv -1 ) ethanol T5; 10% (vv -1 ) ethanol with treatments positioned in rows (A-F) (Primary-tier) (A) or into rows (A-H) and then transferred and Generating and screening Fusarium oxysporum strain 11C transformants. Inoculation of Fusarium oxysporum strain 11C into Mung bean broth [32] for 5 days at 25°C and collection of conidia by filtration through sterile cheesecloth, washing twice with sterile distilled water and adjusting spore concentration to 10 4 conidia per ml (A) Inoculation of Agrobacterium tumefaciens strain AGL-1 to minimal medium (MM) [34] supplemented with Kanamycin (50 μg ml -1 ) for 2 days at 28°C (OD 600nm 0.4-0.6) followed by dilution to OD 600nm of 0.15 in induction medium (IM) [34] supplemented with 200 μM acetosyringone (AS) and incubation for 6 hours at 28°C (B) Co-cultivation of an equal volume of bacterial and fungal cells for 30 minutes at 28°C in liquid co-cultivation medium [34] followed by spreading 100 μl mix onto a UVsterilised cellulose filter membrane placed on solid cocultivation medium on large Petri plates (150x20mm) for 2 days at 25°C where if transformation is successful, T-DNA is transferred from AGL-1 to F. oxysporum strain 11C and randomly integration into the fungal genome results (C) Transfer of cellulose filter membrane to modified selection medium (SM) on large Petri plates (150x20mm) supplemented with 60 hygromycinB for 7-9 days at 25°C followed by isolation of hygromycinB (60 μg ml -1 ) resistant putatively transformed colonies into microtiter (96-well) plates with minimal medium [37] supplemented with hygromycinB (60 μg ml -1 ) for 3 days at 25°C (D) Transfer of putative transformants to microtiter (96-well) plate with minimal medium supplemented with ethanol and butanol selection for primary alcohol tolerance screening followed by purification and PCR prior to two additional rounds of screening (2° and 3°) and selection of candidates for future analysis (E).…”

“…Inoculum was harvested by centrifugation and washed twice with sterile distilled water and resuspended in minimal medium [37] to a concentration of 10 6 ml -1 conidia. Microtiter (96-well) plates were prepared with wells containing 100 μl minimal medium supplemented with either no alcohol, ethanol [2,4,6,8 Figure S1C for plate layout). Each plate was inoculated with 100 μl fungal conidia (10 6 ml -1 ) (eight wells per treatment per wild type/ transformant strain).…”

“…In contrast, filamentous fungi including Trichoderma sp., Neurospora sp., Aspergillus sp., Monilinia sp., Rhizopus sp., Mucor sp., Paecilomyces sp. and Fusarium sp., possess a large repertoire of lignocellulolytic enzymes due to their coevolution with plants, and can convert released plant-derived sugars into ethanol [7][8][9][10]. In particular, the broad host range phytopathogen Fusarium oxysporum [11] can degrade and produce ethanol from various cellulosic substrates (e.g.…”

Advances in consolidated bioprocessing systems for bioethanol and butanol production from biomass: a comprehensive review

“…Fusarium sp., and many white-rot basidiomycetes are capable of producing a large numbers of lignocellulolytic enzymes due to their coevolution with plants, and also possess high abilities to convert released plantderived sugars into ethanol (Lübbehüsen et al, 2004;Dashtban et al, 2009;Fan et al, 2012b;Olson et al, 2012;Hennessy et al, 2013) (Table 3). In the following sub-sections, some single wild type fungi and white rot basidiomycetes as CBP organism for ethanol production from different biomass are presented.…”