Olive-mill wastes are produced by the industry of olive oil production, which is a very important economic activity, particularly for Spain, Italy and Greece, leading to a large environmental problem of current concern in the Mediterranean basin. There is as yet no accepted treatment method for all the wastes generated during olive oil production, mainly due to technical and economical limitations but also the scattered nature of olive mills across the Mediterranean basin. The production of virgin olive oil is expanding worldwide, which will lead to even larger amounts of olive-mill waste, unless new treatment and valorisation technologies are devised. These are encouraged by the trend of current environmental policies, which favour protocols that include valorisation of the waste. This makes biological treatments of particular interest. Thus, research into different biodegradation options for olive-mill wastes and the development of new bioremediation technologies and/or strategies, as well as the valorisation of microbial biotechnology, are all currently needed. This review, whilst presenting a general overview, focusses critically on the most significant recent advances in the various types of biological treatments, the bioremediation technology most commonly applied and the valorisation options, which together will form the pillar for future developments within this field.

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The biosorption of several toxic heavy metals (Pb, Cd, Co, Ni, Zn and Cu) by the exopolysaccharide (EPS) produced by Paenibacillus jamilae, a potential biosorbent for metal remediation and recovery was studied. Firstly, the biochemical composition of this bacterial polymer was determined. Glucose was the most abundant neutral sugar, followed by galactose, rhamnose, fucose and mannose. The polymer presented a high content of uronic acids (28.29%), which may serve as binding sites for divalent cations. The presence of carboxylic groups was also detected by infrared spectroscopy. The EPS presented an interesting affinity for Pb in comparison with the other five metals. Lead biosorption (303.03 mg g -1 ) was tenfold higher (in terms of mg of metal adsorbed per gram of EPS) than the biosorption of the rest of metals. Biosorption kinetics, the effect of pH and the effect of competitive biosorption were determined. Finally, we found that the EPS was able to precipitate Fe(III), but the EPS-metal precipitate did not form with Fe(II), Pb(II), Cd(II), Co(II), Ni(II), Cu(II) and Zn(II).

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Olive oil extraction produces large amounts of residues. These olive-mill wastes are known as alpechin. Alpechin-polluted waste waters are resistant to degradation. They are regarded as a severe environmental problem because of their high organic content, largely simple phenolic compounds that are both antimicrobial and phytotoxic.During the past years, most of the investigations related to alpechin treatment focused on the microbial degradation of the alpechin polyphenols.However, the actual perspectives are based on both the bioremediation of alpechin and on the modification of the technology used in olive-oil extraction. In this article we will describe the most relevant biotreatment systems that can be used for the recycling of alpechin wastes. We will also discuss for each system their prospects for future uses. The various systems we will discuss include the following: (I) Bioremediation for use as fertiliser or soil conditioner. (2) The utilisation as a medium for grown edible mushrooms.

A novel extremely halophilic archaeon was isolated from Lake Tebenquiche, situated in the northern part of the Atacama Saltern, Chile. The cells of these micro-organisms were mostly irregularly disc-shaped. They grew in medium containing saturated concentrations of NaCl and did not require magnesium for optimal growth. The polar lipid composition revealed the presence of mannosyl-2-sulfate-(1-4)-glycosyl-archaeol, the main glycolipid of the genus Halorubrum, and two new glycolipids. The GMC content of the DNA was 63 2 mol %. Phylogenetic analysis of the 16S rRNA gene placed strain ALT6-92 T within the Halorubrum cluster. The low DNA-DNA hybridization value justified classification in a new species for which the name Halorubrum tebenquichense sp. nov. is proposed. The type strain is ALT6-92 T (l CECT 5317 T l DSM 14210 T ).

Endospore-forming strains were isolated from corn-compost treated with olive-mill wastewater (' alpechı! n '). The strains were taxonomically studied and proposed as a novel Paenibacillus species. These organisms (strains B.3 T , B.7 and B.9) were particularly distinguishable from other aerobic spore-forming species by their ability to grow optimally in 100 % (v/v) olive-mill wastewater at 30 SC and pH 70 and concomitant production of an interesting exopolysaccharide. Chemotaxonomic analysis revealed that MK-7 was the predominant menaquinone, the major fatty acid was anteiso C 15 :0 and the cell wall contained meso-diaminopimelic acid. The DNA GMC content was 407 mol %. Comparative sequence analysis of 16S rDNA with different reference species from the genera Bacillus, Paenibacillus, Brevibacillus, Aneurinibacillus, Alicyclobacillus, Halobacillus, Virgibacillus, Amphibacillus, Coprobacillus and Gracilibacillus indicated that the isolated strains were highly related to the genus Paenibacillus. Strain B.3 T formed an evolutionary lineage distinct from other species within the evolutionary radiation encompassing the genus Paenibacillus. Strain B.3 T was a close relative of Paenibacillus polymyxa, but DNA-DNA relatedness data with this species was very low (relative binding ratio T 16 %). Based on the morphological and physiological characteristics, as well as on the phylogenetic position determined by 16S rDNA analysis and DNA-DNA relatedness data, it is concluded that these strains should be designated a novel species, for which the name Paenibacillus jamilae sp. nov. is proposed. The type strain is B.3 T (l CECT 5266 T l DSM 13815 T ).