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This study evaluated the composting process of a mixture of sewage sludge and bulking agent in a semi-closed system at industrial scale, which consisted of an aerated static windrow covered with a semi-permeable film. Physical-chemical and respirometric variables were studied and bacteria and fungi were monitored to assess the improvement in the composting process. The system was compared with conventional open windrows in which lengthy composting times are required to obtain stabilized compost, compost sanitation is not always reached and periodical turning must be carried out to avoid anaerobic conditions. The high temperatures reached and maintained during the stage under the semi-permeable film (≈80 °C) permitted the sanitation of the compostable substrate, as demonstrated by the rapid disappearance of Salmonella sp. and the decrease in Escherichia coli in only 5 days of the process. The total microorganism concentration also decreased during the composting process. The rapid decrease in carbon content expressed in volatile solids (VS) (around 41%) showed that the composting process carried out under the semi-permeable film could be shortened to 30 days. The evolution of thermophilic and mesophilic bacteria and fungi was conditioned by the windrow temperature and the biodegradable organic matter content. An adequate linear correlation (r 2 = 0.9214) between the total microorganism concentration (log CFU/g) and VS (%) was obtained during the composting process. [ABSTRACT FROM AUTHOR]

The global pharmaceutical pollution caused by drug consumption (>100,000 tonnes) and its disposal into the environment is an issue which is currently being addressed by bioremediation techniques, using single or multiple microorganisms. Nevertheless, the low efficiency and the selection of non-compatible species interfere with the success of this methodology. This paper proposes a novel way of obtaining an effective multi-domain co-culture, with the capacity to degrade multi-pharmaceutical compounds simultaneously. To this end, seven microorganisms (fungi and bacteria) previously isolated from sewage sludge were investigated to enhance their degradation performance. All seven strains were factorially mixed and used to assemble different artificial co-cultures. Consequently, 127 artificial co-cultures were established and ranked, based on their fitness performance, by using the BSocial analysis web tool. The individual strains were categorized according to their social behaviour, whose net effect over the remaining strains was defined as 'Positive', 'Negative' or 'Neutral'. To evaluate the emerging-pollutant degradation rate, the best 10 co-cultures, and those which contained the social strains were then challenged with three different Pharmaceutical Active compounds (PhACs): diclofenac, carbamazepine and ketoprofen. The co-cultures with the fungi Penicillium oxalicum XD-3.1 and Penicillium rastrickii were able to degrade PhACs. However, the highest performance (>80% degradation) was obtained by the minimal active microbial consortia consisting of both Penicillium spp., Cladosporium cladosporoides and co-existing bacteria. These consortia transformed the PhACs to derivate molecules through hydroxylation and were released to the media, resulting in a low ecotoxicity effect. High-throughput screening of co-cultures provides a quick, reliable and efficient method to narrow down suitable degradation co-cultures for emerging PhAC contaminants while avoiding toxic metabolic derivatives. [Display omitted] • A direct correlation between the richness, degradation, and toxicity was found. • The minimal active consortium: P. oxalicum, P. rastrickii and C. cladosporoides. • A 5- and 6-species social consortia obtained the highest degradation tested. • Toxicity was greatly reduced with increasing species-rich consortia. [ABSTRACT FROM AUTHOR]

Extracellular polymeric substances (EPS) are one of the main components of microbial biofilms, which are markedly influenced by the chemical composition and functional properties of these EPS. This study quantified the adherence capacity of 29 bacterial strains isolated from marine water in Luria–Bertani and Bushnel-Haas culture media. Their capacity to produce EPS and the influence of the culture conditions on the chemical composition and emulsifying activity of their synthesised exopolymers was determined. Eighteen of the bacterial strains in this study produced EPS while eleven were unable to do so. Surface adherence was associated with bacterial growth and with the capacity of the isolates to synthesise EPS. Pseudoalteromonas elyakovii W18 showed the highest values for surface adherence and synthesised a non-bioemulsifier EPS. Principal component analysis (PCA) was used to establish the relationships between the biopolymer characteristics and surface adherence. The efficient adherence of P elyakovii on the surface of K1 (Anoxkaldnes © ) carrier was confirming by scanning electronic microscopy. [ABSTRACT FROM AUTHOR]