Producing microbial polyhydroxyalkanoate (PHA) biopolyesters in a sustainable manner

Are the thermodynamic parameters correctly estimated in liquid-phase adsorption phenomena?

Background A large amount of wastes and by-products are generated during olive oil production process. Traditionally, these products have been considered as a problem. However, they constitute a great source of high-added value compounds, which have the potential to be used as food additives and/or nutraceuticals. Therefore, valorization of wastes and by-products from food industry kills two birds with one stone and addresses both the use of waste and by-products and societal health, thus greatly contributing for a sustainable food chain from an environmental and economical point of view. Scope and approach In the present review, current and new insights in the recovery of high-added value compounds from wastes and by-products generated during olive oil production process will be discussed. Several conventional (solvent, heat, grinding) and non-conventional methodologies (ultrasounds, microwaves, sub- and supercritical fluid extractions, pressurized liquid extraction, pulsed electric fields and high voltage electrical discharges) have been investigated for the recovery of high-added value compounds (polyphenols, fatty acids, coloring pigments (chlorophylls and carotenoids), tocopherols, phytosterols, squalene, volatile and aromatic compounds) from wastes and by-products generated during olive oil production process. Key findings and conclusions Non-conventional technologies can constitute a promising tool to recover high-added value compounds from olive oil wastes and by-products. However, the content of these valuable compounds can vary greatly depending on the matrix and the efficiency in the recovery of these compounds is highly dependent of the technology used for extraction.

Emerging opportunities for the effective valorization of wastes and by-products generated during olive oil production process: Non-conventional methods for the recovery of high-added value compounds

Aim of the Review. To grasp the fragmented information available on the botany, traditional uses, phytochemistry, pharmacology, and toxicology of Olea europaea to explore its therapeutic potential and future research opportunities. Material and Methods. All the available information on O. europaea was collected via electronic search (using Pubmed, Scirus, Google Scholar, and Web of Science) and a library search. Results. Ethnomedical uses of O. europaea are recorded throughout the world where it has been used to treat various ailments. Phytochemical research had led to the isolation of flavonoids, secoiridoids, iridoids, flavanones, biophenols, triterpenes, benzoic acid derivatives, isochromans, and other classes of secondary metabolites from O. europaea. The plant materials and isolated components have shown a wide spectrum of in vitro and in vivo pharmacological activities like antidiabetic, anticonvulsant, antioxidant, anti-inflammatory, immunomodulatory, analgesic, antimicrobial, antiviral, antihypertensive, anticancer, antihyperglycemic, antinociceptive, gastroprotective, and wound healing activities. Conclusions. O. europaea emerged as a good source of traditional medicine for the treatment of various ailments. The outcomes of phytochemical and pharmacological studies reported in this review will further expand its existing therapeutic potential and provide a convincing support to its future clinical use in modern medicine.

https://downloads.hindawi.com/journals/ecam/2015/541591.pdf

Traditional Uses, Phytochemistry, and Pharmacology of Olea europaea (Olive)

Chitosan as an adhesive

Olive mill wastes: Biochemical characterizations and valorization strategies

Enzymatic degradation and bioactivity evaluation of C-6 oxidized chitosan.

Regarded as biofunctional poly- and oligomers having much higher potential than cellulose in many fields, chitosan and its derivatives have become of great interest thanks to the recent progress in chitin chemistry. Chitosan, which is a natural-based polymer obtained by alkaline deacetylation of chitin, is an interesting bioactive polysaccharide composed of many reactive groups. This gives huge possibilities of chemical modifications to create new derivatives with a broad range of physico-chemical and biological activities. This review gives insights into chitosan, chitosan derivatives and their biological activities. Recent progresses of their chemistry are also discussed as well as biodegradability and environmental assessment concepts applied to these derivatives.

Bioactivity of Chitosan and Its Derivatives

Olive mill wastewater (OMWW), the main waste product of olive oil extraction process, was investigated as a source of polysaccharides. The yield of alcohol insoluble residue (AIR) was 20.5 % based on the dry matter of OMWW. Extraction with water gave water soluble (WSF) and insoluble (WIF) fractions from AIR with yields of 13.3 % (w/w) and 3.7 % (w/w) based on the dry matter, respectively. Chemical composition and monosaccharide analysis indicated that glucose was the main monosaccharide of these extracts in addition to galactose, arabinose, rhamnose, and galacturonic acid. Prebiotic and antioxidant activities of polysaccharidic fractions from OMWW were evaluated. Results gave evidence for their scavenging capacity toward the 2,2'-diphenyl-1-picrylhydrazyle (DPPH) (IC50 value of 89.43 μg/mL) and hydroxyl radicals (IC50 value of 158.70 μg/mL), resistance toward artificial human gastric juice, and ability to be fermented by Lactobacilli strains.

Structural Characterization and Biological Activities of Polysaccharides from Olive Mill Wastewater

The antioxidant properties of phenolic compounds from olive pulp (PCO) of chamlal variety and those of individual phenolic compounds were evaluated and compared with that of vitamin C (Vit C). The antioxidant activity was measured by the tests of iron reduction and scavenging hydrogen peroxide (H2O2). Results showed that all the substances tested exhibit a reducing power. The PCO present activities of iron reduction and H2O2 scavenging higher than those of Vit C. The protective effect of PCO against oxidation of lipids and proteins from erythrocyte membranes was studied. The measurement of malondialdehyde generated under oxidative stress conditions induced by hydroxyl radicals generating system revealed that PCO have the most significant protective activity against lipid peroxidation (IC50 = 49.27 ± 1.91 μg mL−1). Paradoxically, Vit C revealed a pro-oxidant effect. Proteins oxidation was evaluated using the H2O2/FeSO4 system and electrophoresis. In the presence of PCO at 1 mg mL−1, proteins of erythrocyte membranes were protected contrary to those treated with Vit C at the same concentration.

Farida Moulti-Mati

Papers

Olive mill wastes: Biochemical characterizations and valorization strategies

Enzymatic degradation and bioactivity evaluation of C-6 oxidized chitosan.

Bioactivity of Chitosan and Its Derivatives

Structural Characterization and Biological Activities of Polysaccharides from Olive Mill Wastewater

Antioxidant activities of polyphenols extracted from olive (Olea europaea) of chamlal variety.