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The goal of this study was to isolate, select and characterize bacteria with cellulolytic activity from two different coffee residue composting piles, one of which had an internal temperature of 57°C and pH 5.5 and the other, a temperature of 61°C, and pH 9.3. Culture media were manipulated with carboxymethylcellulose and crystalline cellulose as sole carbon sources. The enzyme activity was assessed by hydrolysis halo formation, reducing sugar production and zymograms. Three out of twenty isolated strains showed higher enzymatic activity and were identified as Bacillus subtilis according to their morphological, physiological, biochemical characteristics and based on the sequence analysis of 16S rDNA regions. The enzymatic extracts of the three selected strains showed exocellulase and endocellulase maximum activity of 0.254 and 0.519 U/ml, respectively; the activity of these enzymes was maintained even in acid pH (4.8) and basic (9.3) and at temperatures of up to 60°C. The enzymatic activities observed in this study are within the highest reported for cellulose produced by bacteria of the genus Bacillus. Endocellulase activity was shown in the zymograms from 24h until 144h of incubation. Furthermore, the pH effect on the endocellulase activity is reported for the first time by zymograms. The findings in this study entail the possibility to use these enzymes in the procurement of fermentable substrates for the production of energy from the large amount of residues generated by the coffee agroindustry.

In this work, the white-rot fungus Pleurotus djamor was used for the first time to determine the degradation kinetics of the nonsteroidal anti-inflammatory drugs diclofenac, naproxen and, ketoprofen, either individually or in mixtures, in submerged cultures. Removal of 93% individual diclofenac and 99% diclofenac in mixtures with naproxen and ketoprofen at 6 h of incubation with the fungus was achieved. The elimination levels of naproxen and ketoprofen individually were 90% and 87%, respectively, after 48 h of incubation. However, the removal levels of these compounds in mixtures were 85% and 83%, respectively. On the other hand, during the degradation kinetics analysis, the enzymatic activities of laccases, manganese peroxidases, and lignin peroxidases were evaluated, yielding values of 3700, 270 and 31 U/L, respectively. Additionally, it was demonstrated that during degradation of diclofenac or the three drugs mixed in the submerged cultures, the enzymatic activity of extracellular laccases expressed by P. djamor increased by 200% and 300%, respectively. The activity of manganese peroxides increased by 126% with diclofenac and 138% when the mixture of drugs was added to the cultures. On the other hand, lignin peroxidase only increased activity by 123% with the drug mixture.

In developing countries located in tropical and subtropical regions, the use of ornamental plant species in constructed wetlands (CWs) could add benefits to the treatment of wastewater. This paper presents a study on the efficiency of using plants of economic importance in South Mexico (Heliconia stricta, Heliconia psittacorum and Alpinia purpurata) within an anaerobic digester horizontal subsurface CW system for treating domestic wastewater. The CW with H. psittacorum showed the highest level of removal of biochemical oxygen demand (48%), chemical oxygen demand (64%), total phosphorus (39%) and total nitrogen (39%). This species and H. stricta (which showed slightly lower percentages of removal) may be a viable alternative to using macrophytes in CW in tropical areas such as Chiapas, Mexico.

This paper presents two immobilization methods for the intracellular invertase (INVA), from Zymomonas mobilis. In the first method, a chimeric protein containing the invertase INVA, fused through its C-terminus to CBDCex from Cellulomonas fimi was expressed in Escherichia coli strain BL21 (DE3). INVA was purified and immobilized on crystalline cellulose (Avicel) by means of affinity, in a single step. No changes were detected in optimal pH and temperature when INVA-CBD was immobilized on Avicel, where values of 5.5 and 30 degrees C, respectively, were registered. The kinetic parameters of the INVA-CBD fusion protein were determined in both its free form and when immobilized on Avicel. Km and Vmax were affected with immobilization, since both showed an increase of up to threefold. Additionally, we found that subsequent to immobilization, the INVA-CBD fusion protein was 39% more susceptible to substrate inhibition than INVA-CBD in its free form. The second method of immobilization was achieved by the expression of a 6xHis-tagged invertase purified on Ni-NTA resin, which was then immobilized on Nylon-6 by covalent binding. An optimal pH of 5.5 and a temperature of 30 degrees C were maintained, subsequent to immobilization on Nylon-6 as well as with immobilization on crystalline cellulose. The kinetic parameters relating to Vmax increased up to 5.7-fold, following immobilization, whereas Km increased up to 1.7-fold. The two methods were compared showing that when invertase was immobilized on Nylon-6, its activity was 1.9 times that when immobilized on cellulose for substrate concentrations ranging from 30 to 390 mM of sucrose.