DOI: 10.3303/CET24109071
Paper Received: 3 December 2023; Revised: 27 February 2024; Accepted: 5 April 2024
Please cite this article as: Fatta V., Petrone M.T., Giuliano A., De Bari I., Pierro N., Rosso V., Ocleppo E., 2024, Bioproducts Extraction from
Agro-industrial By-products and Their Valorisation. Development of Process Layouts, Chemical Engineering Transactions, 109, 421-426
DOI:10.3303/CET24109071
CHEMICAL ENGINEERING TRANSACTIONS
VOL. 109, 2024
A publication of
The Italian Association
of Chemical Engineering
Online at www.cetjournal.it
Guest Editors: Leonardo Tognotti, Rubens Maciel Filho, Viatcheslav Kafarov
Copyright © 2024, AIDIC Servizi S.r.l.
ISBN 979-12-81206-09-0; ISSN 2283-9216
Bioproducts Extraction from Agro-Industrial By-Products and
Their Valorisation. Development of Process Layouts
Vittoria Fattaa,*, Maria Teresa Petroneb, Aristide Giulianob, Isabella De Barib, Nicola
Pierrob, Valeria Rossoc, Emanuele Ocleppoc
aItalian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Energy
Technologies and Renewable Sources Department (TERIN), Bioenergy, Biorefinery and Green Chemistry Division (BBC),
Palermo office, Via Principe di Granatelli, 24 90139 Palermo Italy
bItalian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Energy
Technologies and Renewable Sources Department (TERIN), Bioenergy, Biorefinery and Green Chemistry Division (BBC),
Trisaia research centre, S.S. 106 Ionica, km 419+500 75026 Rotondella (MT) Italy
cAsja Ambiente Italia S.p.A. Via Ivrea,70 10098 Rivoli (TO)
vittoria.fatta@enea.it
The agro-food industry generates important quantities of by-products, often considered waste, which represent
for the companies huge costs of handling and disposal. On the other hand, they contain copious amounts and
varieties of compounds that, appropriately extracted, purified, and processed, can be valued in several industrial
sectors. Their exploitation generates an improvement of the sustainability performance of the supply chains,
since it generates economic advantages, making available new commercial products and reducing disposal
costs, improves the environmental performance of the agro-industrial productions, and allows new employment
opportunities, thanks to the development of new industrial sectors. The Percival project aims to valorize the by-
products of agro-industrial supply chains of South of Italy, converting them into high-added value products,
through innovative, efficient, and low environmental impact processes, going for the development of
technologies that could represent new business opportunities for this territory. Particularly, the project deals with
the development of processes for pretreatment, extraction, separation, and chemical/biotechnological
transformation, using a biorefinery cascade approach. Indeed, the study of processes having the purpose of
converting the residues from the above-mentioned transformations into advanced biofuels (biomethane) and
agricultural products (e.g. soil improver and bio-stimulants) are also included in the project’s scope. The present
paper provides an overview of the Percival project, along with the evaluation of the availability of residual
biomasses from the supply chains of typical Southern agricultural products, and the valuable bioproducts
achievable from these feedstocks, through a biorefinery processing scheme.
1. Introduction
The stringent issues of environmental pollution and resources depletion continually push towards the search for
new solutions in term of processes and products. The agro-food industries generate important quantities of by-
products, often considered wastes. They contain large amounts and varieties of compounds that, appropriately
extracted, purified, and processed, can be valued in several industrial sectors, entailing undoubted advantages
on sustainability (Squillaci et al., 2021) of the value chains. First, the use of residual biomass to produce added
value chemical intermediates and/or final products, leads to lower environmental impact than exploiting the fossil
counterparts (Prasetyo et al., 2020) given the use of renewable raw materials. Then, it represents an excellent
opportunity to develop local economic sectors, thanks to the creation of integrated, interconnected, and
interdisciplinary local supply chains (Giuliano et al., 2019) generating new commercial products and creating
new jobs. Finally, the improvement of the environmental performance of agro-industrial productions, mainly due
to the reduction of waste, and the containment of disposal costs can be considered further consequences giving
a positive effect on sustainability. Southern Italy has always had a strong agricultural vocation, therefore the
implementation of processes and innovative technologies to valorize the agro-industrial by-products seems to
421
be one of the most promising development paths for this territory. The conceptual scheme of biorefinery is
potentially capable of making the most of the residual biomass as a source of biochemicals, biomaterials and
bioenergy. Among biochemicals, important building blocks for bioplastics such as lactic acid (Li et al., 2021),
occupy an important place, along with biomolecules for cosmetics and nutraceutical, such as resveratrol (Arias
et al., 2024) and lycopene (Scaglia et al., 2023). Moreover bio-based agrochemicals (soil improvers, bio
stimulants and biopesticides) can be also obtained from waste biomass and replace the synthetic ones, with
undoubted benefits on health and environment (Sojka et al., 2022; Priya et al., 2023). Finally, lignin can be
treated as a source of bio-aromatics and building blocks for functional fibres based on nano-structured materials
(Brienza et al., 2024) and the cascade approach consents to recover for energy and agronomic purposes also
the residues of transformation. The availability and type of agro-industrial biomass residues is not constant over
time due to the climatic and phytosanitary conditions and market fluctuations. Indeed, these factors affect the
yield and productivity of biomass, the collection, and transformation activities, and, consequently, the quantity
of by-products. Therefore, appropriate methods of evaluation of the availability of residual biomasses from the
different agro-industrial supply chains should be applied, to verify the technical-economic feasibility of a project
aimed at valorizing agricultural by-products. The aim of Percival project (Processi di EstRazione di bioprodotti
da sCarti agroIndustriali e VALorizzazione in cascata) is the valorization of the by-products of agro-industrial
supply chains of South of Italy, through the development of innovative, efficient, and low environmental impact
processes, to convert these feedstocks into high-added value products, according to a biorefinery scheme. In
this work an overview of the project was presented, and some preliminary results of the activities were
discussed. In particular, the quantities of by-products obtainable from the supply chains of three relevant
agricultural products of South of Italy were calculated. Then, for each product, a biorefinery flowsheet draft was
presented and discussed.
2. The Percival project
The Percival’s goal is the valorisation of by-products, originating from agro-industrial supply chains typical of the
South of Italy, through the production of biochemicals, biomaterials, and biofuel. For this purpose, the activities
of the project consist in developing efficient and low environmental impact production processes, as pre-
treatment, extraction, and fractionation, based on chemical and biotechnological cascade transformation,
interconnected and integrated, according to a biorefinery scheme. Feedstocks include processing residues from
some of the main agricultural supply chains of South of Italy, such as citrus fruits, wine, tomatoes, apples etc.,
while, the range of the obtainable products the project focuses on encompasses building blocks for the bioplastic
markets, such as polylactic acid and succinic acid, as well as pectin, lycopene, volatile fatty acids, and bioactive
compound for the cosmetic, nutraceutical, and agronomic sectors (antioxidants, resveratrol, bioammendants,
biostimulants, and biocides). In addition, other products considered are lignin-based biomaterials, biomethane,
and biochar. The study of separation, purification, and characterization techniques of the above-mentioned
products are also activities covered by the project. Moreover, in vitro evaluations of the bioactive agronomic
molecules are carried out, individually and/or as formulates in association with other natural ingredients, to
quantify their effects in the agricultural productions of the South of Italy. At the same time, long-term stability,
bioavailability, efficacy are tested in prototypal cosmetics and nutraceutical products. Finally, life cycle
assessment, cost analysis and market trends are elaborated for industrial applications. Percival project is
articulated into five activity lines, and each of them is divided into several sub-lines. Figure 1 shows the project
structure and the flows of data/results among the lines.
3. Materials and Methods
3.1 Availability of agro-industrial by-products in Southern Italy
To estimate the potential production of some target biomolecules, the availability in Southern Italy of residual
biomass from wine, citrus and tomato agroindustry was carried out, based on a methodology developed by
ENEA, (Motola et al., 2009; Pierro et al., 2021). The sources of residual agricultural biomass in a given territory
can be huge and of different nature. Given this variability, the estimation of the quantities obtainable is often
subject to great uncertainty. Among the many variables affecting the actual annual availability of agricultural
residual biomass there are climatic factors, the productivity of agricultural crops, the amount of residues actually
usable, and that already destined for other purposes.
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The Figure 1: Structure of Percival project
The methodology applied in the present work evaluates the theoretical potential, which is the total amount of
biomass that can be produced (or formed) within physical and biological constraints (Brosowsky et al., 2020).
According to this methodological approach, the by-products of agricultural and agro-industrial activities are
associated with the areas where their agricultural reference products are collected, even if sometimes they can
be produced in a different place, for example where the reference products are manufactured. The residual
biomasses evaluated in the present study were wine pomace, wine grapes pruning, citrus pomace, citrus
pruning, tomato peels, and tomato seeds. The methodology applied for the evaluation of the potential availability
of wine pomace, wine grapes pruning, citrus pomace, citrus pruning, tomato peels is based on the formula:
Theoretical potential availability = Harvested Production * Residue to product ratios (1)
Where:
• Harvested Production is the mass of product harvested on the area under production (ISTATa);
• Residue to product ratios is the ratio between the masses of product and by-product reported by
literature (Motola et al., 2009; Pierro et al., 2021).
The assessment of wine lees, which are deposits of dead yeast or residual yeast and other materials that are
left over after the fermentation process used to make wine, is made considering the production of wine on a
regional scale, surveyed by ISTAT (ISTATa), and the coefficients reported by literature (Bevilacqua et al., 2017).
Furthermore, the assessment of tomato seeds potential derives from a literature review (Casa et al., 2021) and
data from ISTAT (ISTATa).
3.2 Agro-industrial residues conversion to target products
Biomass residues can be converted into several bioproducts, that depend on specific characteristics of the
starting material. The selected target products from the conversion of residues of the supply chains described
in the previous section can be grouped in three kinds of compounds:
• high-added value compounds: i.e. resveratrol, antioxidants, and lycopene;
• biopolymers' precursors and bio-based fibers: lactic acid, precursor of poly lactic acid (PLA), volatile
fatty acids, precursors of polyhydroxybutyrate/polyhydroxyalkanoate (PHB/PHA) and lignin based
fibers;
• energy vectors/biofuels: biomethane, and biochar/hydrochar.
To obtain these products, several process pathways can be considered using a cascade approach. In a valued-
added cascade approach, the first step is the extraction of the high-added value compounds that are present in
the feedstock in a very small quantity (0.1-2.0 %). A next step could regard the valorization of the solid residues
coming from the extraction, through biomethane’s production via anaerobic digestion and biogas upgrading.
Moreover, the processing of the lignocellulosic streams, leading to second-generation sugars platform, from
which LA and PLA can be obtained, offers a further possibility of by-products valorization. Finally, the residues
of the last two treatments, poor in structured compounds (cellulose, lignin, sugars, proteins), but with a residual
423
high content in carbon, can in turn be valorized by producing biochar or hydrochar, the latter through a
thermochemical process such as the hydrothermal carbonization (HTC), and lignin-based fibers respectively.
4. Preliminary results
4.1 Agro-industrial residual biomass availability in Southern Italy
The table 1 shows the results of the availability analysis of residual biomass from wine, citrus, and tomato supply
chain in Southern Italy. The Italian regions with the greatest availability of residues, deriving from the wine supply
chain are Apulia and Sicily. As regards the citrus supply chain, the Regions with the greatest availability of
residual biomass are Sicily, Calabria, and Apulia. Instead, the biomass deriving from the tomato processing
supply chain is more abundant in Apulia and Campania. The strong agricultural vocation of Southern Italy,
confirmed by the data of the latest agricultural census of 2020 (ISTATb), where almost 50% of the used
agricultural surface is found in the South and in the Islands, determine the potential presence of a high quantity
of residues (Table 1), The valorization of such residues, according to a cascade approach, in which all biomass
components are transformed into high-value products, and there are no valueless wastes, represents an
economically and environmentally much more advantageous alternative compared to their disposal in landfill.
All this resolved to be in accordance with new European directives, such as the Renewable energy directive EU
2023/2413 and the Waste Frame Directive.
Table 1: Theoretical potential, at regional scale, of evaluated biomass expressed in tons of wet material (t
w.m.), 2022.
Grape
marc
(tw.m.)
Wine Lees
(tw.m.)
Wine grapes
Pruning
(tw.m.)
Citrus
Pomace
(tw.m.)
Citrus
Pruning
(tw.m.)
Tomato
Peels
(tw.m.)
Tomato
Seeds
(tw.m.)
Molise 49’203 3’078 23’057 66 34 1’976 1’373
Apulia 245’730 65’079 456’409 159’112 99’833 44’021 30’591
Basilicata 2’734 518 4’153 61’759 36’110 3’482 2’419
Calabria 6’627 1’619 15’625 595’067 316’336 3’296 2’290
Campania 154’879 8’855 72’308 19’002 12’451 7’035 4’889
Sicily 186’229 35’287 288’100 759’015 198’094 2’267 1’575
Sardinia 9’512 4’106 79’114 31’893 8’757 1’168 811
4.2 Cascade valorization of Agro-industrial residual biomass
Using the methodology of section 2.2, biorefinery’s schemes were assessed for the byproducts’ valorization of
wine, citrus, and tomato supply chains. Figure 1 shows the identified opportunities derived from the application
of a cascade methodology, through block flow diagrams. Process design methodologies were applied to assess
the multi product biorefinery based approach (Giuliano et al, 2015). Processes were selected based on the
research focus of the Percival Project. The techno-economic and environmental feasibility of the defined multi-
products layouts will be assessed as part of future developments. From the grape marc and wine lees quantified
in section 3.1, (Figure 1.a), resveratrol extraction by ultrasound-assisted extraction (UAE) was first proposed
(Singh et al., 2017). Then, since the residual solid (about 80-90 %wt) of the extraction is a good substrate for
anaerobic digestion (AD), it was assumed to obtain biogas and subsequently biomethane. The latter is an
energy-product, and it can be blended with natural gas in the grid, as, after the upgrading, its concentration can
be >99%vol. Moreover, for the digestate, having a high content in carbon, the conversion into hydrochar by HTC
was proposed. The other byproduct from the wine agroindustry consists of pruning lignocellulosic material
having a content of cellulose/hemicellulose/lignin of 21, 12 and 30 % respectively (Jesus et al., 2022). According
to the scheme in Fig. 1a, after pretreatment and fractionation, enzymatic hydrolysis was used to convert
cellulose/hemicellulose to 2nd generation sugars. Then, polylactic acid was produced by the sugars' fermentation
to lactic acid, followed by polymerization. Lastly, the other stream from hydrolysis, consisting of a lignin-rich
stream, was used to produce fibers as target product. Figure 1.b shows the biorefinery flow sheet hypothesized
for the valorization of tomato agroindustry residues i.e. tomato peels and seeds. The first one has a high content
of lycopene and pectin (Casa et al., 2021b), which were extracted by supercritical CO2 and acid, respectively.
Regarding the seeds, they were considered as a substrate to produce volatile fatty acids by AD. These
chemicals are the precursors of polyhydroxybutyrate/polyhydroxyalkanoate (PHA/PHB), polymers belonging to
424
the polyesters class, which are of interest as bio-based and biodegradable plastics. Moreover, also in this case,
the solids from digestate were used to produce hydrochar by HTC. As far as the Citrus fruit agroindustry is
concerned, it can provide two main residual materials, the pomace, containing antioxidant molecules, and the
pruning. According to the block flow diagram in Fig. 1c, a similar cascade valorization procedure, as the wine
agroindustry, was proposed for them: extraction of antioxidants from the pomace, AD of extraction’s residues,
biogas upgrading to biomethane, HTC of the digestate to hydrochar, while from pruning, PLA and lignin-based
fibers were produced. Based on some literature data and on the results of table 1, an estimate of the production
potential of southern Italy was obtained regarding some of the above-mentioned products. In particular,
antioxidants compounds could be produced for about 3-4 kt/y, biopolymers in the range of 350 – 450 kt/y and
biomethane until to 2.5 107 GJ/y. Furthermore, the quantities of pectin and lycopene that could be produced
from tomato peels amount to 0,63 t/y and 0,38 t/y respectively.
Figure 2: Block Flow Diagram for the cascade valorisation of residues from three agroindustry supply chains of
South Italy: Wine (a), Tomato (b), Citrus fruits (c)
5. Conclusions and future works
Different by-products can be produced from agro-industrial activities and processes. These residual biomasses
that often represent an economic and environmental problem, can be the source of large amounts and varieties
of valuable products. Southern Italy, with its agricultural vocation, can be a suitable place for the development
of an industry for the transformation and valorization of agro-industrial by-products, that would generate
economic, social, and environmental benefits. The Percival project takes advantage from the synergy between
research institutions and companies, for the development of innovative processes, devoted to the production of
biochemicals, biomaterials and biofuels from the by-products of the agricultural supply chains typical of South
of Italy. In this work the outcomes of the first project's activities were reported. In particular, the availability of
the by-products of wine, citrus, and tomato supply chains in Southern Italy was calculated, concluding that the
quantities involved make the exploitation of this by-products feasible. Techno-economic analysis and
environmental analysis will be part of future publications.
(a)
(b)
(c)
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Acknowledgments
The present work is part of the national project PERCIVAL funded through the program PON 2014-2020.
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Bioproducts Extraction from Agro-Industrial By-Products and Their Valorisation. Development of Process Layouts