Sustainable Use of Citrus Waste as Organic Amendment in Orange Orchards

Abstract

The use of citrus waste (peel, CW) as organic fertilizer was investigated on soil microbiota and on soil physico-chemical and hydraulic characteristics. The biotic components on CW and the effect on nutritional status, leaf chlorophyll content, fruit set and production of “Tarocco” orange trees were also identified. The citrus waste was supplied to an experimental orchard at different doses: 45 kg m−2 (with and without Ca(OH)2 addition) and 90 kg m−2. The study was conducted in three consecutive years (2015–2017) on 20-year old orange trees at the experimental farm of the University of Catania (Italy). The main results of the study confirm that the use of CW as a biofertilizer offers a great opportunity for sustainable sweet orange production.

Pulsed electric field technology as a promising pre-treatment for enhancing orange agro-industrial waste biorefinery

“…Therefore, biorefinery strategies to valorize orange processing waste has been increasingly explored in recent research. 12,54–56…”

“…52,57–59 By utilizing non-thermal processes, these unconventional technologies reduce the energy demand and aid in the preservation of heat-sensitive components. 54–56…”

“…4,7 Therefore, harnessing OPW holds significant promise in fostering sustainable innovation and ensuring economic viability within the realm of bioproduct development. 54 However, the production of these by-products from OPW encounters several challenges. The high production costs require significant investments in research, development, and production, potentially impacting the final product cost.…”

“…Therefore, the typical fate of this material is treatment and subsequent disposal in the environment. 54 However, several studies shown many opportunities being investigated to valorize citrus wastewater. This allows for the consideration of reusing the waste components to obtain dyes, antioxidants, nutraceuticals, antimicrobials, and flavorings.…”

The citrus economy in Sicily in the early bioeconomy era: a case study for bioeconomy practitioners

“…40 This dynamic situation has also been reflected in the bioeconomic research carried out in Sicily in the last decade (2012-2022) by researchers at universities and research institutes based in Sicily, on the valorization of citrus processing waste. Selected achievements include the discovery of microwave-assisted 41 and hydrodynamic cavitation-assisted 42 (HC-assisted) extraction processes carried out in water alone to obtain pectin, cellulose, biophenols and EOs; the optimization of biogas production from WOP, 36 and from industrial wastewater; 37 the use of WOP as source of cellulose (extracted with hydrogen peroxide under basic conditions) to make textile fibers; 43 the use of WOP as soil biofertilizer, 44 and to produce thermal insulating panels for the construction industry. 45 Clearly, in a island with high solar irradiation levels like Sicily, there is room for the utilization of value-adding conversion technologies applied to WOP using solar energy such as that developed by Chemat, Mandi, and co-workers, again employing water as the only extraction medium.…”