Presence of microbes on utensils.

Posted by On Filed under Microbial Community Thinglink individual posts, Uncategorized No Comments

Layman’s Terms:

Microscopic organisms are everywhere, even in places where you would think they wouldn’t be, such as on clean clothes, clean kitchen counters or even washed utensils. Do you remember those advertisements for disinfectants that claim they can kill 99.9% of bacteria? You might think that 0.1% are left there even after using these antibacterial disinfectants. In Ontario, they have a standard that on a cleaned utensil there should not be more than 100 bacterial cells! Imagine what happens to utensils cleaned in dishwashers without such effective disinfectants! A study was done by scientists in Ontario, Canada on the dishwashers which did not handle a lot of utensils at an instance, such as those in residential care homes. Along with disinfectants, high temperature is also needed to kill microorganisms which is a strategy that dishwashers actually use. But in establishments that have relatively few utensils, household dishwashers are sometimes used instead of commercial dishwashers. The household dishwashers cannot always achieve such high temperatures which means that they need to use sanitizers to treat utensils. The sanitizer has to be used at a set time and concentration but normal dishwashers do not have this function. The study found that 83% of these dishwashers actually worked within the prescribed limits but still there are 17%, that is, more than 1 out of 6 instances that your utensils actually contain a lot of microbes. So the next time you take the utensils out from the dishwasher, think again if they are clean or not. Also, if you live in residential care facilities or places that use common dishwashers then you might ask that they install a commercial sized dishwasher instead of domestic dishwasher.

Technical Explanation:

The researchers aimed to study cleaning ability of domestic dishwashers employed in residential care homes. The researchers focused on these places because they know that dishwashers do not work that well if there are fewer utensils cleaned at a time. This happens due to low temperature that water reaches when cleaning occurs. A temperature of 82oC for 10 seconds or chemical sanitization at 24oC is required to properly sanitize the utensils. For samples, they chose 4 establishments with different numbers of dishwashing units to a total of 103 units. Four different types of utensils were selected for the study and were swabbed after one full cycle was over. Standard operating procedures laid out by United States Public Health Service’s (USPHS) were followed. Of the 103 domestic dishwashers evaluated, 85 (83%) yielded results that fell within the prescribed limit of no more than 100 bacterial colonies per utensil as determined by heterotrophic plate count (HPC). Dishwashers that contained utensils classified as somewhat soiled or very soiled before washing were more likely to fail (P < 0.05) than those that were classified as very clean or somewhat clean before washing when all other characteristics and operating parameters and the number of plastic items were controlled for. With increasing maximum rinse temperature, dishwashers were less likely to fail (P < 0.05) while the same characteristics were controlled for. Also, dishwashers were more likely to fail when chlorinated detergents were used (P < 0.05). So even after using a dishwasher on dirty utensils, there is a 16% chance that it will not be as clean as the required standards and we have to use sanitizer in the dishwasher to get the desired results.

Citation:
https://www.foodprotection.org/wp-content/uploads/sites/763/food-protection-trends/May-Jun-15-sahai.pdf

Bioremediation of PAHs-contaminated soil through composting: Influence of bioaugmentation and biostimulation on contaminant biodegradation

Posted by On Filed under Contaminant biodegradation (round 2) papers No Comments

Link:

https://www.sciencedirect.com/science/article/pii/S0964830511001326

Abstract:

The degradation of several polycyclic aromatic hydrocarbons (PAHs) in soil through   composting was investigated. The selected PAHs included: fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, and chrysene, with concentrations simulating a real creosote sample. The degradation of PAHs (initial concentration 1  g of total PAHs kg−1  dry soil) was assessed applying bioaugmentation with the white-rot fungi  Trametes versicolor  and biostimulation using compost of the source-selected organic fraction of municipal solid waste (OFMSW) and rabbit food as organic co-substrates. The process performance during 30 days of incubation was evaluated through different analyses including: dynamic respiration index (DRI), cumulative oxygen consumption during 5 days (AT5), enzymatic activity, and fungal biomass. These analyses demonstrated that the introduced  T.  versicolor  did not significantly enhance the degradation of PAHs. However, biostimulation was able to improve the PAHs degradation: 89% of the total PAHs were degraded by the end of the composting period (30 days) compared to the only 29.5% that was achieved by the soil indigenous microorganisms without any co-substrate (control, not amended). Indeed, the results showed that stable compost from the OFMSW has a greater potential to enhance the degradation of PAHs compared to non-stable co-substrates such as rabbit food.

Justification:

I selected this paper because it deal with Polycyclic aromatic hydrocarbons, which is the topic discussed in recent classes. The paper talks about composting as another method for contaminant degradation which I found very interesting.

Citation:

Lukić, B.,  Huguenot, D.,  Panico, A.,  van Hullebusch, E.D.,  Esposito, G., 2017. Influence of activated sewage sludge amendment on PAH removal efficiency from a naturally contaminated soil: application of the landfarming treatment.  Environmental Technology (United Kingdom), 38(23), pp. 2988-2998

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Bioremediation of Uranium-Bearing Wastewater: Biochemical and Chemical Factors Influencing Bioprocess Application

Posted by On Filed under Biodegradation and bioremediation papers No Comments

Abstract:

A biotechnological process for the removal of heavy metals from aqueous solution utilizes enzymatically liberated phosphate ligand which precipitates with heavy metals (M) as cell’bound MHPO4. The enzyme, a phosphatase, obeys Michaelis’Menten kinetics in resting and immobilized cells; an integrated form of the Michaelis’Menten equation was used to calculate the apparent  Km  (Km app.) as operating in immobilized cells in flow’through columns by a ratio method based on the use of two enzyme loadings (Eo1,  Eo2) or two input substrate concentrations (So1,  So2). The calculated  Km app.  (4.08 mM) was substituted into an equation to describe the removal of metals by immobilized cells. In operation the activity of the bioreactor was in accordance with that predicted mathematically, within 10%. The initial tests were done at neutral pH, whereas the pH of industrial wastewaters is often low; an increase in the  Km app.  at low pH was found in previous studies. Immobilized cells were challenged with acidic mine drainage wastewaters, where the limiting factors were chemical and not biochemical. Bioreactors initially lost activity in this water, but recovered to remove uranyl ion with more than 70% efficiency under steady’state conditions in the presence of competing cations and anions. Possible reasons for the bioreactor recovery are chemical crystallization factors.

Link:  https://onlinelibrary.wiley.com/doi/epdf/10.1002/%28SICI%291097-0290%2819970105%2953%3A1%3C100%3A%3AAID-BIT13%3E3.0.CO%3B2-S

Citation:  Fernando I. Ramírez-Paredes,  Teresa Manzano-Muñoz,  Juan C. Garcia-Prieto,  Galina G. Zhadan,  Valery L. Shnyrov,  John F. Kennedy and  Manuel G. Roig,  Biosorption of heavy metals from acid mine drainage onto biopolymers (chitin and α (1,3) β-D-glucan) from industrial biowaste exhausted brewer’s yeasts (Saccharomyces cerevisiae L.),  Biotechnology and Bioprocess Engineering,16, 6,  (1262)

 

This is an old paper from mid 90’s that gives us an insight on how heavy metals are removed from wastewater by immobilized cells. I found this paper interesting because it explained the chemistry of enzymes secreted by microbes pretty well.

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Biodegradation and removal of pharmaceuticals and personal care products in treatment systems: a review

Posted by On Filed under Biodegradation and bioremediation papers No Comments

Abstract:
Pharmaceuticals and personal care products (PPCPs) have been the focus of much recent research as concerns rise about their occurrence in bodies of water worldwide. In an effort to characterize the risk and determine the prevalence of these micropollutants in lakes and rivers, many researchers are examining PPCP removal from impaired water during wastewater treatment and water recycling (soil passage) processes. Biodegradation studies and projects considering combinations of biodegradation and other removal processes have been conducted over a wide range of compound categories and therapeutic classes, as well as across different systems and scales of study. This review summarizes the extent of PPCP removal observed in these various systems.

Link:  https://link.springer.com/article/10.1007%2Fs10532-008-9237-8

Citation:

Ladislav Mandaric, Elena Diamantini, Elisa Stella, Karina Cano-Paoli, Jennifer Valle-Sistac, Daniel Molins-Delgado, Alberto Bellin, Gabriele Chiogna, Bruno Majone, M. Silvia Diaz-Cruz, Sergi Sabater, Damia Barcelo and Mira Petrovic

Journal:  Science of The Total Environment, 2017, Volume 590-591, Page 484

DOI:  10.1016/j.scitotenv.2017.02.185

I chose this article because in our recent trip to WWTP, we discussed about these micropollutants present in water and the challenges that WWTP has to face in removing them.

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Presence of microbes on utensils.

Posted by On Filed under Microbial Community Thinglink individual posts No Comments

Layman’s Term:

Microscopic organisms are everywhere. Even in places where you would think they are not. Like clean clothes, clean kitchen counters or even washed utensils. Remember those advertisements which claim that they kill 99.9% bacteria. You might think still 0.1% are left there even after using antibacterial disinfectants. In Ontario, they have a standard that on a cleaned utensil there should not be more than 100 bacterial colonies! Imagine what happens to utensils cleaned by us in dishwashers which does not even use those kinds of disinfectants! A study was done by scientists in Ontario, Canada on the dishwashers which did not handle a lot of utensils at an instance. So if you are living in a family daycare services, or residential care home, this article is for you. Along with disinfectants, high temperature is also needed to kill microorganisms which the dishwashers actually use. But in places where the utensils are not that much, the dishwashers cannot achieve that temperature. Also, if low temperature is used to treat utensils then sanitizer has to be used at a set time and concentration but normal dishwashers do not have this function. So, if you live in any of these places then you might ask that they install a commercial sized dishwasher instead of domestic dishwasher. The study found that 83% of these dishwashers actually worked within the prescribed limits but still there are 17%, that is, more than 1 out of 6 instances that your utensils are actually not clean and contain a lot of unwanted stuff.

 

Technical Explanation:

This paper aimed at the study of cleaning ability of domestic dishwashers employed in residential care homes. The researchers picked these places because they know that dishwashers do not work that good if there are less utensils cleaned at a time. This happens due to low temperature that water reaches when cleaning occurs. A temperature of 82oC for 10 seconds or chemical sanitization at 24oC is required to properly sanitize the utensils. For samples, they chose 4 establishments with different number of dishwashing units to a total of 103 units. 4 different types of utensils were selected for the study and were swabbed after one full cycle was over. Standard operating procedures laid out by United States Public Health Service’s (USPHS) were followed. Of the 103 domestic dishwashers evaluated, 85 (83%) yielded results that fell within the prescribed limit of no more than 100 bacterial colonies per utensil as determined by heterotrophic plate count (HPC). Dishwashers that contained utensils classified as somewhat soiled or very soiled before washing were more likely to fail (P < 0.05) than those that were classified as very clean or somewhat clean before washing, when all other characteristics and operating parameters and the number of plastic items were controlled for. With increasing maximum rinse temperature, dishwashers were less likely to fail (P < 0.05) while the same characteristics were controlled for. Also, dishwashers were more likely to fail when chlorinated detergents were used (P < 0.05).

 

Citation:
https://www.foodprotection.org/wp-content/uploads/sites/763/food-protection-trends/May-Jun-15-sahai.pdf

Thousands of microbial genomes shed light on interconnected biogeochemical processes in an aquifer system

Posted by On Filed under Biogeochemical cycling papers No Comments

Link:  https://www.nature.com/articles/ncomms13219


Abstract:

The subterranean world hosts up to one-fifth of all biomass, including microbial communities that drive transformations central to Earth’s biogeochemical cycles. However, little is known about how complex microbial communities in such environments are structured, and how inter-organism interactions shape ecosystem function. Here we apply terabase-scale cultivation-independent metagenomics to aquifer sediments and groundwater, and reconstruct 2,540 draft-quality, near-complete and complete strain-resolved genomes that represent the majority of known bacterial phyla as well as 47 newly discovered phylum-level lineages. Metabolic analyses spanning this vast phylogenetic diversity and representing up to 36% of organisms detected in the system are used to document the distribution of pathways in coexisting organisms. Consistent with prior findings indicating metabolic handoffs in simple consortia, we find that few organisms within the community can conduct multiple sequential redox transformations. As environmental conditions change, different assemblages of organisms are selected for, altering linkages among the major biogeochemical cycles.

Citation:

Parks, D.H.,  Rinke, C.,  Chuvochina, M., (…),  Hugenholtz, P.,  Tyson, G.W., “Recovery of nearly 8,000 metagenome-assembled genomes substantially expands the tree of life”,  Nature Microbiology 2(11), pp. 1533-1542

 

Reason for selecting this paper:

This paper gives a good insight about the microbial communities living in aquifers and how do they interact with each other. Underground water is an important source of water to humans and this paper discusses about changes in biogeochemical cycles.

 

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Hello everyone. I am Ankur Sachan and I am from India. I am currently pursuing M.S. degree in Mining Engineering. My research topic is biodegradation of Alaskan coal to extract rare earth elements. My hobbies include cooking Indian food, driving and travelling (I admit I like flights!!)   to new places.

Haiku:

I realized on flight

I ran tests for a month

Now, the microbes are dying.

This is a beach in Andaman and Nicobar islands in India where I went this winter break. This beach is famous for bioluminescent bacteria and it glows in night when water is disturbed. I do not have the photograph of night, but trust me it is awesome when you look at it in person!!!