A sus­tain­able approach to turn­ing renew­able plant resources into defos­sil­ised materials

Coun­tries are unit­ing in the fight against cli­mate change, aim­ing to drastic­ally cut green­house gas emis­sions by 2030 and reach net zero by 2050. A major step towards this goal is build­ing eco­nom­ies that rely on renew­able resources. Bio­lo­gic­al sys­tems nat­ur­ally recycle green­house gas emis­sions while gen­er­at­ing an array of chem­ic­als and mater­i­als. Bio­man­u­fac­tur­ing har­nesses this capa­city by employ­ing microor­gan­isms and enzymes to trans­form renew­able biore­sources into fuels, plat­form chem­ic­als and bio-based altern­at­ives to plastics. By 2030, bio­tech­no­lo­gies driv­ing these innov­a­tions are expec­ted to pro­duce over 35 % of the chem­ic­als and mater­i­als we use daily. The EU-fun­ded BioUP­GRADE pro­ject integ­rated com­pu­ta­tion­al bio­logy, gen­om­ics and mater­i­al sci­ences to devel­op biotechnology’s poten­tial in sus­tain­able man­u­fac­tur­ing, focus­ing on biocata­lysts (enzymes) that con­vert renew­able fibres into high-value products.

Upgrad­ing instead of break­ing down

“We tar­geted the devel­op­ment of biocata­lysts that upgrade renew­able biore­sources into valu­able mater­i­als rather than break­ing them down,” notes pro­ject coordin­at­or Emma Mas­ter. ​“Tra­di­tion­ally, enzymes used in bio­mass pro­cessing are designed to degrade plant mater­i­al into sug­ars, which are then fer­men­ted into fuels and chem­ic­als. How­ever, this ​‘break-it-down first’ paradigm is both costly and inef­fi­cient in terms of atom eco­nomy.” Instead, BioUPGRADE’s advanced enzymes that tail­or the nat­ur­al struc­ture of bio­mass to make it suit­able for a wider range of uses, such as pack­aging mater­i­als, con­duct­ive inks for bio­elec­tron­ics and hydro­gels for health and per­son­al care. ​“This approach improves mater­i­al effi­ciency and reduces the envir­on­ment­al impact com­pared to tra­di­tion­al chem­ic­al pro­cesses,” adds Master.

Mak­ing bet­ter use of nat­ur­al resources

A key research activ­ity was design­ing biocata­lysts that can modi­fy the struc­ture and chem­ic­al prop­er­ties of nat­ur­al mater­i­als such as cel­lu­lose, hemi­cel­lu­lose and chitin. To achieve this, research­ers ana­lysed both pub­licly avail­able and in-house gen­om­ic data­sets. They used advanced tech­niques such as com­par­ing gen­omes across spe­cies (com­par­at­ive gen­om­ics), recon­struct­ing ancient enzyme sequences (ances­tral sequence resur­rec­tion) and run­ning molecu­lar sim­u­la­tions to under­stand how these enzymes work. A key out­come was a com­pu­ta­tion­al frame­work that designs cus­tom multi-func­tion­al pro­teins and helps identi­fy key bio­phys­ic­al fea­tures of enzymes that act on mater­i­al sur­faces. ​“Judi­cious design and imple­ment­a­tion of applic­a­tion-driv­en func­tion­al screens is cent­ral to any biocata­lyst devel­op­ment frame­work,” states Mas­ter. ​“To this end, we cre­ated micro-scale plat­forms that identi­fy biocata­lysts that can pre­cisely modi­fy the phys­ic­al prop­er­ties, such as sur­face charge, poros­ity and flow beha­viour, as well as the chem­ic­al fea­tures, like adding car­bonyl or amine groups, of struc­tur­al polysaccharides.”

Reviv­ing ances­tral enzymes for new applications

A prom­in­ent example of biocata­lyst devel­op­ment is the design­ing and test­ing of ances­tral enzymes, includ­ing expansins, endo­glu­canase and lyt­ic poly­sac­char­ide monooxy­genase. These ances­tral ver­sions dis­played unique prop­er­ties not present in mod­ern enzymes, which rep­res­ent advant­ages for bio­tech­no­lo­gic­al applic­a­tions. Con­sid­er­able efforts were also ded­ic­ated to scal­ing up pro­tein pro­duc­tion. Micro­bi­al expansins were pro­duced in biore­act­ors ran­ging from 5 to 200 L, provid­ing enough mater­i­al for ini­tial applic­a­tion tri­als in cel­lu­lose fibre pro­cessing. The approach exports the pro­tein dir­ectly into the extra­cel­lu­lar envir­on­ment, enabling high yields without the need for com­plex puri­fic­a­tion steps. BioUP­GRADE cross-dis­cip­lin­ary col­lab­or­a­tion led to more tar­geted, adapt­able and pre­dict­able tech­no­lo­gies for cre­at­ing func­tion­al mater­i­als. Unlike tra­di­tion­al meth­ods that break down plant mater­i­als into sug­ars, the pro­ject uses enzymes to select­ively modi­fy under­used bio­mass rather than con­vert it to sug­ars, boost­ing resource effi­ciency and sup­port­ing reuse for a more sus­tain­able bioeconomy.