Non Technical Summary
Given the increasing demands for wood in green building construction, there is an urgent need for more environmentally benign wood protection approaches, especially for exterior conditions. Preventative preservative treatment is the most economically viable way to increase carbon sequestration in wooden buildings while maintaining a resilient and sustainable built environment. However, alternative environmentally and economically friendly solutions for wood protection have yet to be developed. The overall objective of this project is to engineer bio-based preservatives of agricultural origin, in particular, from potato peel wastes (PPW) extracts, through laccase-assisted enzymatic bio-grafting for increased durability of wood under outdoor conditions. The supporting objectives are to: (1) develop durable wooden material by enzymatic grafting of PPW extracts and (2) elucidate the antimicrobial mechanism of PPW extracts against common wood-decaying fungi. Our central hypothesis is that non-durable wood grafted with PPW extracts with the aid of laccase enzyme will have increased durability and reduce environmental impacts while helping contribute to sustainable bioeconomy development in both potato and forest product industries in the State of Idaho and beyond. Our approach will have significant positive effects by "producing biobased products to enable bioeconomy" with "extended carbon sequestration" and reduced environmental impacts, which aligns with the emphasis area of the Sustainable Bioeconomy through Biobased Products (A1414) program area priority.

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
605	0650	2020	30%
123	0650	1103	40%
403	0650	2000	30%

Knowledge Area
403 - Waste Disposal, Recycling, and Reuse; 605 - Natural Resource and Environmental Economics; 123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0650 - Wood and wood products;

Field Of Science
2020 - Engineering; 1103 - Other microbiology; 2000 - Chemistry;

Goals / Objectives
Theoverall objective of this projectis to engineer bio-based preservatives of agricultural origin, in particular, from potato peel wastes(PPW) extracts, through laccase-assisted enzymatic bio-grafting for increased durability of woodunder outdoor conditions.The supporting objectives are to:(1) develop durable wooden material by enzymatic grafting ofPPW extracts and (2) elucidatethe antimicrobial mechanism ofPPW extracts against commonwood-decaying fungi.This research willallow us to establish key parameters for the development of next-generation durable woodeninfrastructure materials under outdoor conditions.

Project Methods
Supporting Objective #1 (SO1) Develop durable wood material by enzymatic grafting of PPW extractives. This objective will be attained by five tasks (SO1-1 to SO1-5) listed below:(SO1-1) Biological active compounds Extraction from Potato Peel Wastes. The biologically active compounds from PPW will be extracted using an established simple and green extraction technique, known as indirect ultrasound-assisted extraction [50,51].(SO1-2) Enzymatic grafting of PPW extracts in wood structure. Before grafting PPW extractives to wood, the potential bonding between the individual compounds in wood (cellulose, hemicellulose, and lignin) and PPW extractives with the aid of the laccase-catalyzed bio-grafting will be investigated using two complementary analytical techniques: 1) FTIR and 2) solution/solid-state 1H/13C nuclear magnetic resonance (NMR) spectroscopies [53]. Upon elucidating the PPW extractives locking mechanism, we will treat wood samples with PPW extracts using laccase enzyme from T. versicolor [10,11]. For wood treatment, three factors dominating the laccase grafting between wood and PPW extracts will be investigated. These factors are 1) the concentration of PPW extracts used for wood sample treatment (CPPW,1% to 10%), 2) treating time (t, 24 h to 72 h), and 3) laccase/mediator ratio (r, 0.5 to 2.5).(SO1-3)Study the penetrability of PPW extractives in wood structures. The effectiveness of a wood preservative penetration will be evaluated by determining the amount of preservatives retained (mass gain). Specifically, the freeze-dried mass of the samples before and after the treatment will be measured to calculate the mass gain.(SO1-4) Evaluate PPW extractives bonding to wood and resistance to leaching and dimensional stability. Similar to the procedures stated in SO1-1, chemical bonding between PPW extractives and wood following the laccase-assisted grafting will be elucidated by FTIR and NMR spectroscopies. Before exposure to fungi, the long-term performance of PPW extractives-treated wood will be tested following the leaching procedures described in American Wood Protection Association (AWPA) Standard E11-16 [57].(SO1-5) Examine the fungal resistance of PPW extractives-treated wood. The fungal resistance of the PPW extractives-treated wood will be evaluated per AWPA E10 standard [58]. Samples with no significant mass loss as compared to the untreated and unexposed samples are considered protected.(SO1) Expected Outcomes: It is expected that the completion of all SO1 tasks will result in a comprehensive understanding of the interaction between PPW extracts and wood upon the enzyme grafting for improved long-term wood durability. This knowledge will lay a foundation for the development of novel durable wooden infrastructure that aims at combating wood-decaying fungi.Supporting Objective #2?(SO2)Elucidate the antimicrobial mechanism of PPW extracts against four common wood-decaying fungi, which will be attained by three tasks (SO2-1 to SO2-3)::(SO2-1)Determine minimum inhibitory concentrations of PPW extracts against four common wood-decaying fungi. The biological activities of PPW extracts will be rapidly screened using malt agar as substrate (in vitro) [60]. We will first determine the minimum inhibitory concentrations of PPW extracts against various wood-decaying fungi.(SO2-2) Assess levels of fungal reactive oxygen species (ROS) production, enzymatic activity responses, and metabolite changes following PPW extracts treatment. To understand the fungal physiological response of PPW extracts-treated fungi that leads to growth inhibition, we will first investigate the release of ROS as outlined in Lopez et al. [66].(SO2-3) Observation of cellular morphological changes following PPW extracts treatment. Fungal culture slides will be prepared based on our previous experience [60,68,69], and then subjected to light and fluorescence microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) based on previously established steps [70].(SO2) Expected Outcomes: The expected accomplishments of supporting objective #2 are to 1) yield new knowledge of minimum inhibition concentrations of PPW extracts that will impede fungal growth, and 2) yield an improved understanding of the antimicrobial mechanism of PPW extracts against common wood-decaying fungi, which will enable the future development of improved wood protection strategies.