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The 2-phase Chemlali olive pomace is selected as substrate for chemical treatment. Treatment of "alperujo" using water bath or autoclave apparatus was carried out. A high amount of hydroxytyrosol was obtained using autoclave apparatus.

Microbial production of bioplastics, derived from poly(3-hydroxybutyrate) (PHB), have provided a promising alternative towards plastic pollution. Compared to other extremophiles, halophilic archaea are considered as cell factories for PHB production by using renewable, inexpensive carbon sources, thus decreasing the fermentation cost. This study is aimed at screening 33 halophilic archaea isolated from three enrichment cultures from Tunisian hypersaline lake, Chott El Jerid, using starch as the sole carbon source by Nile Red/Sudan Black staining and further confirmed by PCR amplification of phaC and phaE polymerase genes. 14 isolates have been recognized as positive candidates for PHA production and detected during both seasons. The identification of these strains through 16S rRNA gene analyses showed their affiliation to Halorubrum, Natrinema, and Haloarcula genera. Among them, three PHB-producing strains, CEJ34-14, CEJ5-14, and CEJ48-10, related to Halorubrum chaoviator, Natrinema pallidum, and Haloarcula tradensis were found to be the best ones reaching values of 9.25, 7.11, and 1.42% of cell dry weight (CDW), respectively. Our findings highlighted that Halorubrum, Natrinema, and Haloarcula genera were promising candidates for PHB production using soluble starch as a carbon source under high salinity (250 g L-1 NaCl).

BACKGROUND: The three-phase extraction process of olive oil produces highly contaminated wastewater (OMW). The elimination of this toxic by-product is an important environmental issue that requires the development of an appropriate management solution. The cultivation of microalgae using OMW as growth medium was therefore studied using single (the culture medium was formed by 0% to 80% ultrafiltered olive mill wastewater (OMUF) or OMW added to BG11) and two-stage strategies (microalgae were firstly cultivated in the BG11 medium. In the second stage, 40% and 80% of OMUF and OMW were added to the culture). In this work, biodegradation of OMW and subsequent extraction of lipid and antioxidant molecules was investigated as an ecofriendly method for the bioremediation and valorization of OMW.RESULTS: For two-stage cultivation, OMUF and OMW stress enhanced the intracellular amount of polyphenol accumulated in Scenedesmus sp. and exhibited the highest 2, 2-diphenyl−1-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzoline-6-sulfonate) radical (ABTS) scavenging ability compared with single-stage cultivation. Moreover, the lipid profile is dominated by polyunsaturated acids. In the single-stage cultivation, the Ch a, Ch b, carotenoid, carbohydrate and lipid content of 2.57, 7.4, 1.69, 368, and 644 g kg −1 were observed in 40% OMUF added culture, respectively, along with high biomass productivity and 58% of polyphenol removal. Moreover, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that the biomass of Scenedesmus sp. cultured on 40% OMUF did not show any toxic effect, making it an efficient strategy. CONCLUSION:The results indicate that Scenedesmus sp. is a promising microalga for the biotreatment of OMW and the extraction of bioactive metabolites.