Fungal decomposition of chicken-feather waste in submerged and solid-state fermentation

Poultry industry is expanding rapidly and producing million tons of feather waste annually. Massive production of keratinaceous byproducts in the form of industrial wastes throughout the world necessitates its justified utilization. Chemical treatment of keratin waste is proclaimed as an eco-destructive approach by various researchers since it generates secondary pollutants. Keratinase released by a variety of microbes (bacteria and fungi) can be used for the effective treatment of keratin waste. Microbial degradation of keratin waste is an emerging and eco-friendly approach and offers dual benefits, i.e., treatment of recalcitrant pollutant (keratin) and procurement of a commercially important enzyme (keratinase). This study involves the isolation, characterization, and potential utility of fungal species for the degradation of chicken-feather waste through submerged and solid-state fermentation. The isolated fungus was identified and characterized as Aspergillus (A.) flavus. In a trial of 30 days, it was appeared that 74 and 8% feather weight was reduced through sub-merged and solid-state fermentation, respectively by A. flavus. The pH of the growth media in submerged fermentation was changed from 4.8 to 8.35. The exploited application of keratinolytic microbes is, therefore, recommended for the treatment of keratinaceous wastes to achieve dual benefits of remediation.

Prevalence of and risk factors for respiratory symptoms in an adult urban population

OBJECTIVE: To determine prevalence of and risk factors for respiratory symptoms in an adult urban Pakistani population.METHODS: We conducted a multi-stage, community-based, cross-sectional survey from May 2014 to August 2015, comprising 1629 adults from 75 random clusters in Karachi using questionnaire-based interviews.RESULTS: Around 60% of participants were females and 43% belonged to the >37 years age group. At least one respiratory symptom was reported by 37.5% of participants. Breathlessness was the most common symptom (25.2%, 95%CI 23.1-27.3), followed by acute wheeze (10.1%, 95%CI 8.7-11.7). Multivariable models revealed that males and those aged >37 years were more likely to report acute and chronic phlegm and bronchitis, and breathlessness. Participants with a higher level of education were less likely to report acute and chronic cough. Participants with >5 years pack-years of smoking were more likely to report acute and chronic cough and breathlessness. Other risk factors included passive smoking, regular use of air conditioning and mosquito coils, wet spots and mould in the house, and exposure to dusty jobs.CONCLUSION: We found breathlessness to be the most prevalent respiratory symptom and identified various risk factors for respiratory symptoms.

Indoor air quality and its relationship with cluster type in urban Pakistani households

OBJECTIVE: To assess the levels and predictors of formaldehyde, nitrogen dioxide (NO₂), carbon monoxide (CO) and fine particulate matter with diameter less than 2.5 μm (PM2.5) in Karachi, Pakistan.METHODS: A total of 1629 households were selected through multistage cluster sampling in a community-based cross-sectional survey. Formaldehyde, NO₂ and CO levels were measured using YesAir Indoor air monitor and for PM2.5, UCB-PATS (University of California Berkeley Particle and Temperature Sensor) was used. Clusters were classified either as planned (areas of planned housing) or unplanned (informal settlements).RESULTS: We found the median concentrations to be as follows: formaldehyde, 0.03 ppm (IQR 0.00-0.090); CO, 0.00 ppm (IQR 0.00-1.00); NO₂, 0 ppm (IQR 0.00-0.00) and PM2.5, 0.278 mg/m³ (IQR 0.162-0.526). We found a significant association of the upper quartiles of formaldehyde and PM2.5 levels with type of cluster. The risk of obtaining formaldehyde and PM2.5 levels in the upper quartile was higher in unplanned clusters than in planned clusters (adjusted odds ratio [aOR] 33.0, 95% CI 4.02-271.5 and aOR 0.10, 95% CI 0.001-0.16, respectively). No significant association was observed between levels of CO and cluster type (aOR 0.84, 95%CI 0.62-1.14).CONCLUSION: This study reports high levels of indoor air pollutants in Karachi, with considerable variation across planned vs. unplanned clusters.