Valorization of Greenhouse Horticulture Waste from a Biorefinery Perspective

Abstract

Greenhouse cultivation and harvesting generate considerable amounts of organic waste, including vegetal waste from plants and discarded products. This study evaluated the residues derived from tomato cultivation practices in Almería (Spain) as sugar-rich raw materials for biorefineries. First, lignocellulose-based residues were subjected to an alkali-catalyzed extrusion process in a twin-screw extruder (100 °C and 6–12% (w/w) NaOH) to assess maximum sugar recovery during the subsequent enzymatic hydrolysis step. A high saccharification yield was reached when using an alkali concentration of 12% (w/w), releasing up to 81% of the initial glucan. Second, the discarded tomato residue was crushed and centrifuged to collect both the juice and the pulp fractions. The juice contained 39.4 g of sugars per 100 g of dry culled tomato, while the pulp yielded an extra 9.1 g of sugars per 100 g of dry culled tomato after an enzymatic hydrolysis process. The results presented herein show the potential of using horticulture waste as an attractive sugar source for biorefineries, including lignocellulose-based residues when effective fractionation processes, such as reactive extrusion technology, are available.

Efficient use of discarded vegetal residues as cost-effective feedstocks for microbial oil production

“…(Almería, Spain) and were obtained under greenhouse farming conditions. The carbohydrate content of the discarded vegetables was determined following methods described elsewhere [18]. The residues were crushed by homogenization in a Danamix TR/bM-330 industrial blender (SAMMIC; Azkoitia, Spain), and the resulting solid and liquid fractions were subsequently separated by centrifugation at 3000 rpm for 15 min, using a basket centrifuge RTL2BD (COMTEIFA; Barcelona, Spain).…”

“…In this context, using these residues as feedstocks for yeast cultivation represents an attractive alternative with potential application in the energy sector. Carbohydrates from discarded vegetable products can be easily extracted by collecting the corresponding juice after a crushing procedure [18]. In this work, discarded pepper, tomato and watermelon were studied as raw material for accumulating intracellular lipids using the oleaginous yeast Cryptococcus curvatus.…”

Evaluation and Identification of Key Economic Bottlenecks for Cost-Effective Microbial Oil Production from Fruit and Vegetable Residues

“…The carbohydrate content of the DPW fractions was analyzed following methods described elsewhere [13]. Sugar composition of the raw material and pulses, as well as the monitoring of sugar consumption by the yeast, was analyzed using HPLC Waters Alliance 2695 equipment, with a refractive index detector (detector 2414) equipped with a Carbo Sep CHO 782 chromatographic column (Transgenomic, Omaha, NE, USA) at a temperature of 70 • C. Degassed ultrapure water with 0.5 mL/min flow was used as a mobile phase.…”

Sustainable Drying and Green Deep Eutectic Extraction of Carotenoids from Tomato Pomace

“…Carotenoids are naturally present in tomatoes; among these is lycopene, which is mainly responsible for the red color of the fruit with a claimed nutraceutical effect [12], and it also appears to act as a powerful antioxidant, preventing the action of free radicals and carcinogenic cells [13,14]. Tomato can play an important role in valorization of by-products, not only for feedstock and production of biofuels [15][16][17], but also through the extraction of important compounds, including lycopene [18]. In fact, lycopene can be used in cosmetic preparations due to its properties of reducing lipid oxidation and preventing damage related to the action of UV rays [18].…”