A highly original research project—on developing joint production of edible mushroom and biofuel—is receiving attention as a top-of-the-line innovation effort in Sweden, as part of the country's aim to develop new technologies and processes for a circular bioeconomy.
A Bio4Energy researcher at the Swedish University of Agricultural Sciences invented the concept, which rests on the idea that both production strands would be more cost effective and environmentally friendly if they were made in synergy.
If this turns out to be the case—if and when the proposed process and the technologies it relies on have been proven—Sweden could become a net producer of edible mushroom and rely less on imports, all the while making cost-competitive ethanol biofuel.
The Swedish national innovation platform BioInnovation funds a part of the project called Comush, which runs from autumn 2017 until autumn 2020. It sorts under the heading BioEconomy 2.0, Better Valorisation of Residual Streams.
The research concept entails growing fungi such as shiitake or oyster mushrooms on wood or forestry residue. The mushroom will break down the polymer lignin in the wood so that another main polymer—cellulose—may be separated out and turned into bioethanol, in an ulterior step.
A main achievement by the Comush project has been to find a way to cleanse the wood of impurities before the start of fungal growth, which is less costly and required less energy than outright sterilisation. Instead, the wood is pre-treated with hot air in a closed chamber, in a procedure tantamount to pasteurisation. Such cleansing is necessary to allow the mushroom to grow without being crowded out by other organisms on the wood surface.
“We have at this time a way to maximise lignin degradation, but minimising cellulose breakdown”, Xiong said.
It was a research "breakthrough", according to Xiong, described in a scientific article about to be published.
While it is not yet clear just how effective the new combined process will be when fully developed, Xiong said that "it should be competitive with biofuel technologies on the market". A company called BioSteam is the main industrial project partner and will own the patents in the process of being granted.
“We are working together with several industrial partners and applying for funds from Jordbruksverket (the Swedish Board of Agriculture) and from other sources to be able to further develop the processes and technologies for harvest, pasteurisation and industrial processing. After that we hope to be going onto [large-scale industrial] demonstration trials”, according to Xiong.
Relevant scientific articles (more will be added as they are published)
Chen F, Xiong Sh, Gandla ML, Stagge S, Martín C. 2021. Spent mushroom substrates for ethanol production – effect of chemical and structural factors on enzymatic saccharification and ethanolic fermentation of Lentinula edodes-pretreated hardwood. Bioresource Technology 126381. 20 November
Chen F, Grimm A, Eilertsen L, Martín C, Arshadi M, Xiong Sh. 2021. Integrated production of edible mushroom (Auricularia auricular-judae), fermentable sugar and solid biofuel. Renewable Energy 170, 172-180. June
Grimm A, Eilertsen L, Chen F et al. 2020. Cultivation of Pleurotus ostreatus Mushroom on Substrates Made of Cellulose Fibre Rejects: Product Quality and Spent Substrate Fuel Properties. Waste Biomass Valor. 3 December
Chen F, Martín C, Finell M et al. 2020. Enabling efficient bioconversion of birch biomass by Lentinula edodes: regulatory roles of nitrogen and bark additions on mushroom production and cellulose saccharification. Biomass Conv. Bioref. June
Chen F, Xiong Sh, Sundelin J, Martín C, Hultberg M. 2020. Potential for combined production of food and biofuel: Cultivation of Pleurotus pulmonarius on soft- and hardwood sawdusts. Journal of Cleaner Production, 266, 122011. September
Wei M, Xiong Sh, Chen F, Geladi P, Eilertsen L, Myronycheva O, Lestander TA, Thyrel M. 2020. Energy smart hot-air pasteurisation as effective as energy intense autoclaving for fungal preprocessing of lignocellulose feedstock for bioethanol fuel production. Renewable Energy, 155, 237-247. August
Xiong Sh, Martín C, Eilertsen L, Wei M, Myronycheva O, Larsson SH, Lestander TA, Atterhem L, Jönsson LJ. 2019. Energy-efficient substrate pasteurisation for combined production of shiitake mushroom (Lentinula edodes) and bioethanol. Bioresource Technology, 274, 65-72. February
BioInnovations årsrapport 2019, pages 8 and 9
IVA Aktuellt Nr 6, 2019 - Årets bästa forskning och teknik, page 24