PhycoFib – sustainable fibrous materials from microalgae

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Sustainability and environmental impact concerns have led to a growing demand for alternatives to oil-based plastic packaging. In the UK, paper and board for packaging are primarily manufactured from pulp obtained from recovered paper. A progressive loss of strength occurs during recycling due to cellulose fibre damage, necessitating the use of imported materials to address the shortfall. Alternative sources of fibre suitable for use in paper and board manufacture are desirable to meet growing demands, whilst increased UK-based production will help reduce the environmental impact of importation.Previous work has demonstrated that pulp can be strengthened by addition of cellulose fibres processed to increase their slenderness and degree of fibrillation. Presently, the production of materials with these features, such as highly fibrillated cellulose fibres (HFCFs), microfibrillated cellulose (MFC) and nanocellulose (NC), is energy intensive and prohibitively expensive. Furthermore, the quantities available are insufficient to meet industry needs.The project aims to establish the feasibility of using microalgae as a sustainable source of fibre for use by the paper industry. Microalgae such as _Chlorella_ can be rapidly grown in large quantities and processed to provide a sustainable source of oils, protein and other high-value chemicals with diverse applications. The lack of lignin in the residual cell wall material favours production of MFC or NC for the manufacture of lighter, stronger packaging. This is highly desirable because transportation costs and associated greenhouse gas emissions are reduced. Exploitation of the residual cell wall materials would also enable a zero-waste solution for microalgal biorefineries.We have previously demonstrated that mechanical cavitation (MCav) of pulp and agri-food by-products is an efficient method of recovering valuable materials whilst increasing cellulose fibrillation and paper strength. MCav of microalgal suspensions would be compatible with existing methods of material handling within paper mills, minimising the requirement for novel equipment and capital expenditure. The project will examine the performance of MCav when applied to selected species of microalgae with diverse characteristics (for example oil and protein content, cell wall composition) to establish their suitability for paper manufacture. The algal fibres obtained will be added to recovered paper and the impact on mechanical strength measured. Chemical and biological pre-processing methods such as enzyme pre-treatment will also be examined as a means of enhancing production efficiency, cost-effectiveness and product performance.In addition to the economic and environmental benefits, this study will aid progress towards net-zero carbon emissions and a circular bio-economy.