The bioeconomy: Fungal biotechnology and wood lignocellulosic biomass

An iamge of forestry to demonstrate the bioeconomy
© iStock/thekopmylife

According to the bioeconomy model, fungal biotechnology allows the environmentally friendly conversion of ligocellulosic biomass in higher value-added compounds.

The role of biotechnology in the global economy, promoted by the technological advances of the last decade, has enormously contributed to the bioeconomy, which refers to all economic activities based on the invention, development, production and use of processes and products of biological origin.

Advances in high throughput genomics, genetic and biological engineering, as well as synthetic biology are transforming the landscape of industrial and environmental processes. Micro-organisms, enzymes, and their products are replacing chemical-dependent processes. However, perhaps the greatest attention is focused on the applications of biotechnology in agriculture and industry.

Furthermore, the bioeconomy works for sustainable development based on the use of renewable resources, and in that sense lignocellulose biomass could become a good source for green chemicals and biomaterials.

The increasing volume of lignocellulosic residues coming from the agroforestry activity around the world has led to the study and development of strategies to ensure the sustainable use of this biomass in the obtaining of added value products. In recent years, lignocellulosic biomass has received significant attention as a renewable resource to reduce dependence on fossil fuels and produce renewable chemicals.

However, biomass pretreatment remains an essential step in added value product production due to the fact that lignin removal is required to access cellulose and hemicellulose, the main components of biomass. Micro-organisms, including some groups of bacteria and many fungi, have metabolic capacities to degrade lignocelullose in a natural way.

Opportunities and benefits

The bioeconomy offers enormous opportunities for developing countries since they could convert their primary economy based on natural resources exploitation to a biotechnology-based economy for increasing resource productivity, especially for the production of biofuels, food, natural compounds, enzymes, biofertilisers and others, to solve the need for technological innovation and supplies for textile, leather, and paper industries, and the design and optimisation of waste conversion processes in products of economic value.

Moreover, megadiverse countries could place economic value on their biological species and genetic resources through a knowledge-based economy. However, success in this goal, promoted by the global economic environment, will depend to a large extent on their local technological capabilities.

Latin America

In Peru, although investment in science and technology is still very low compared with other Latin American countries (accounting for only around 0.08-0.11% of GDP), government funding agencies have increased their participation to promote research and innovation initiatives.

In this context, the Laboratory of Mycology and Biotechnology of National Agrarian University La Molina, which has over 40 years’ experience in research into industrial biotechnologies, is conducting a research project supported by INNOVATE PERU to use wood residues for the production of cellulolytic enzymes for textile use with the collaboration of the National Technological Innovation Center for Wood (CITE MADERA).

Added value from residue

Although Peru has around 68 million hectares of natural forests, the rational use of them only contributes to around 0.5% of the country’s economy. Around 40 thousand hectares have been reforested with native species, mainly Bolaina Blanca, to be used mainly in the manufacture of furniture, which is an improvement in added value. But residues generated by the wood industry from Bolaina constitute a source of environmental contamination because they are often discarded in rivers. According to the bioeconomy concept, it is possible to develop an integrated production system (see Fig. 1), which allows the use of energy with the least environmental damage to be maximised in such a way that all components of the system benefit.

We propose a solution to the problem based on the industrial use of processing waste from Bolaina to generate enzymes as a main product with high demand and better market price.
Until now, Peru has needed to import industrial enzymes as there is no national production. Indeed, over the last three years, the country has paid more than US$33.5m (~€29.5m) to import these enzymes.

Biological depolymerisation

Although wood residues constitute a renewable resource for industrial use, physical or chemical treatment is required to remove lignin and deconstruct cellulose to make it more accessible for further microbial conversion. The main goal of our research is thus to replace physicochemical treatment with biological one.

The biological depolymerisation of lignin using fungal cultures requires the secretion of several oxidative enzymes such as laccases, manganese peroxidases (MnP), lignin peroxidases (LiP), versatile peroxidases (VP, aryl-alcohol oxidases (AAO) and glyoxal oxidases, amongst others, usually produced by white rot fungi such as Trametes sp., Ceriporiopsis sp., and Phanerochaete. We have isolated and sequenced a strain of Trametes polyzona with high capacity to remove lignin from wood residues.

Following the biological treatment of wood residues, we have optimised mixed cultures of native strains of Aspergillus niger and Trichoderma solid state fermentation (surface adhesion fermentation). Classical statistical optimising strategies were assisted by trasncriptomics to evaluate cellulases’ gene expression.

Confocal laser scanning microscopy (CSLM), fourier trasnform infrared spetroscopic analysis (ftir) and mass spectrometry MS-TOF are being used to evaluate lignocellulose deconstruction. CSLM pictures in Fig. 2 show T. polyzona growing on white bolaina (Guazuma crinita) by solid state fermentation (a) and (b) sclerenchyma cells of bolaina broken by Trametes enzymes.

FTIR spectrum suggests that biological treatment with T. polyzona-modified lignin structure of wood, while cellulose and hemicellulose had little or no modification. This result indicates that the fungus T. polyzona has high potential to modify the lignin probably due to its enzymatic machinery of oxidases and peroxidases.

After that, co-culture of Aspergillus and Trichoderma allows the production of cellulase, mainly endoglucnases, for use in the textile industry.

Since then, we have found that enzymes can be recovered without solid residues, and that nanocellulose crystals (NCC) can be obtained by centrifugation. NCC is useful to obtain composites for several biomaterials.

The project is supported by the Ministry of Production through INNOVATE PERU. Grant No. 063-INNOVATEPERU-IAPIP-2017

Professor Gretty K Villena
Director
Ilanit Samolski
Professor and Researcher
Laboratory of Mycology
and Biotechnology
Universidad Nacional Agraria La Molina (LMB-UNALM)
Maria Lucila Hernandez
Macedo Professor
Universidade Tiradentes (UNIT)
+51 1 6147800 ext 463
gkvch@lamolina.edu.pe
isamolski@lamolina.edu.pe
lucyherma@gmail.com
http://web.lamolina.edu.pe/lmb/

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