Date palm (Phoenix dactylifera L.) is an important crop in arid and semiarid regions. Date palm fruits constitute the principal source of remuneration and the basis of the economy for people living in the Tunisian Sahara. Phoenix dactylifera is a member of the family Arecaceae, also known as Palmaceae. It is well known that the average weight of date seeds is about 10-15% of date weight [1]. The fruit of the date palm is composed of a fleshy pericarp and seed. The edible part of date fruit is fleshy mesocarp, which exists in-between the epicarp and hard endocarp. Mesocarp of date fruit has more than 80% sugars and the remaining 20% has dietetic fibers, protein, Pol. J. Environ. Stud. Vol. 28, No. 1 (2019), 267-274 AbstractThe seeds of 11 common dates (phoenix dactylifera L.) cultivars from the coastal oasis of Gabés, and the noble variety Deglet Nour from the oasis of Kébéli were evaluated for their chemical composition. Polyphenol, flavonoid, anthocyanin, antioxidant, and antimicrobial activity was recorded against 5 pathogen bacteria (Escherichia coli, staphylococcus aureus, staphylococcus epidermis, and Salmonella Typhinurium). The sugar content ranged between 1.20 g/100 gMS ( Bouhattam) and 3.80 g/100 gMS ( Khadhouri). The total phenolic content oscillates between 5.224 g/100 gMS (Baht) and 9.532 g/100 gMS (Khadhouri). Khadhouri also had the highest total flavonoids content (3.82 g/100 gMS). The higher antioxidant activity was found on the Khadhouri cultivar (55.47% of DPPH radical scavenging activity). It has been found that a linear relationship (p<0.01) exists between total phenolic content and inhibition percentage. Antibacterial avtivities clearly show that all the extracts showed antibacterial activity except Enterococcus feacalis. PCA revealed that the first two principal components (PC1 and PC2) accounted for 54.23% of the total variance within the data set. These two principal components separated the studied cultivars into four different groups. This by-product of date processing industries could be regarded as an excellent source of food ingredients with interesting technological functionality that could also be used in medicinal preparation as an important source of oil.

Biocontrol research has the potential for managing Fusarium root rot of olive. This latter is treated by the use of isolated bacteria from the soil of olive orchards of Tunisia: Bacillus Licheniformis and Enterobacter Colcae. It was demonstrated that these two bacteria are effective against Fusarium solani and oxysporum. In an initial screening, two efficacy bacteria were isolated with a reduction of disease incidence. In vitro, both biocontrol agents were highly tolerant to the carbendazime fungicide commonly used to control Fusarium diseases. It was observed that carbendazime reduced disease symptoms at a concentration of >50 µg mL −1. The combination of the bacterial isolates and carbendazime gave a significant (P≤0, 05) control of the disease when plants were artificially inoculated with the pathogen. The application of carbendazime at a low concentration (10 µg mL −1) in combination with Bacillus B4 reduced disease symptoms by 51%, compared with a reduction of 46% obtained with the bacterium alone and no control with the chemical treatment alone. A combination of Bacillus with fungicide increased the application rate of 10 µg mL −1 carbendazime and significantly reduced disease symptoms by 74% compared to 34% with carbendazime treatment alone and, respectively, a combination fungicide and Enterobacter E4 increased the disease by 84% compared with 55% for bacteria alone. In this experiment, the integrated treatment also slightly outperformed the application of 100 µg mL −1 bacteria Bacillus and Enterobcater applied, and without fungicide also provided good disease control.