Anaerobic digestion of cheese whey: Energetic and nutritional potential for the dairy sector in developing countries.

Cheese whey (CW) is the main waste generated in the cheesemaking process and has high organic matter content and acidity. Therefore, CW disposal is a challenge for small to medium enterprises (SMEs) in the dairy industry that do not have any type of treatment plant. Anaerobic digestion (AD) is an attractive process for solving this problem. The aim of this research was to determine the biomethane and struvite precipitation potentials of CW from four dairy SMEs. First, changes in CW properties (organic matter and pH) were evaluated. Second, biomethane and struvite potentials were assessed using cattle slurry as inoculum. The organic matter in CW varied from 40 to 65gVS/kg, 65 to 140g COD/L, and 2 to 10g/L for VFAs depending on the sampling time and type of sample. The pH of the CW samples ranged from 3 to 6.5. In the anaerobic biodegradability analysis, methane yields reached 0.51 to 0.60L CH4/g VSadded, which represented electrical and caloric potentials of 54 and 108kWh/m3 for CW, respectively. Organic matter removal in all experiments was above 83%. Moreover, anaerobic digestates presented NH4+/PO43- molar ratios between 2.6 and 4.0, which are adequate for struvite precipitation with potential production of 8.5-10.4g struvite/L CW. Finally, the use of biogas as energetic supplement and struvite as soil fertilizer, represents economics saves of US$ 6.91/m3 CW and US$ 5.75/m3 CW in therms of electricity and fertilizer use, respectively. The energetic, agricultural and economic potentials, evidence that AD process is a feasible alternative for cheese whey treatment.

Polymorphisms of pro-inflammatory cytokine genes and the risk for acute suppurative or chronic nonsuppurative apical periodontitis in a Colombian population.

AIM: To determine the association of functional single nucleotide polymorphisms in genes of the pro-inflammatory cytokines tumour necrosis factor-α, interleukin-1ß, interleukin-8 and interleukin-12B with the development of two clinical forms of apical periodontitis (AP): acute suppurative and chronic nonsuppurative. METHODOLOGY: The study included 120 patients from Bucaramanga City, Colombia, 63 diagnosed with acute suppurative AP (ASAP) and 57 diagnosed with chronic nonsuppurative AP (CNAP). Genotyping for IL1B +3954 (rs1143634), IL8 / CXCL8 -251 (rs4073), IL12B +1188 (rs3212227) and TNFA -308 (rs1800629) was performed by the PCR-restriction fragment length polymorphisms method. The statistical analysis was performed using STATA 10.0 and PLINK V1.07 software. RESULTS: Significant differences in the distribution of IL8 / CXCL8 -251 A allele (P adjusted = 0.041; OR adjusted = 0.41, CI adjusted = 0.31-0.97) and IL8 / CXCL -251 TT genotype (P adjusted = 0.04; OR adjusted = 2.24, CI adjusted = 1.04-4.84) were observed comparing patients diagnosed with ASAP and CNAP. No association was observed in genotype and allele distribution for other genetic polymorphisms analysed. CONCLUSION: This study provides molecular epidemiological evidence that suggests in the present cohort that IL8 / CXCL8 -251 T allele, which is associated with higher production of IL8/CXCL8, is also associated with a higher risk of developing acute suppurative form of AP, whereas IL8 / CXCL8 -251 A allele, which is associated with lower production of IL8/CXCL8, is associated with chronic nonsuppurative form of AP. This suggests a pivotal role for IL-8/CXCL8 in periapical disease because of its ability to induce chemotaxis and modulating the directed migration of neutrophils to the site of inflammation in response to microbial infection of pulp.