There is no such biocide, in fact you must know which kind of pathogen you're having in your sample in order to chose the appropriate biocide. There are biocide for gram positive bacteria and for gram negative ones. What can kill one kind of bacteria can be metabolized for the other. The same thing happen with fungi, there is one kind of fungicide for filamentous fungi and other very different for yeasts, and even within the filamentous ones several species are sensitive to azoles and other ones are resistant.. And think about this, if you want a general biocide to kill every kind of microorganisms then you will damage the organisms you're working with, especially their cell walls, so you have to know what microbial pathogen you're having problems with to chose the biocide... Sorry there is no other way than cultivate it and make tests... Hope this may be usefull for you

Can you be more specific re. "environmentally-safe" in the context of your application?   The term has no technical meaning per se.

Which surfaces do you refer to? Working space? Skin? May the substances be volatile? Please tell us more on your intentions.

Hi there,

Sodium hypochlorite is the universal antiseptic. Depending on what you have to decontaminate, you could use different concentration of it including Dakin solution (hypochlorite 0.5%+permanganate)...

Thank u all for ur response. Yes sir Environment safe means of it should not harm any aquatic forms and to humans,so it has to be specific for organisms only..and Dr.Johannes: It should not volatile sir and I will use it for polymerization process. It is not for any medical use.

Thanks in advance.

I personally do not understand what do you want? You will use the agent for killing pathogenic microbes and then for polymerization??? What the hell are you working on? Do you really know what are you doing?

- How do you identify your pathogenic mic. (specify method)

- Specify aquatic source (river, lake, waste water,...)

- Why exactly do you want to destroy cell wall?

- Bacteriophages can be very specific against certain bac. strains, while not doing any damage to human cells.

So if you will not provide us specific with details, we can not help you. But I am afraid that you are asking wrong questions.

i suggest you to use physial treatment instead of chemicals, Some chemicals like phonols, alcohols and acids can remove any biological agants from any surface but it's temporary and microbs will be back soon. you want not volatile and not harm to human. then it's better u use physial treatment such as higher tempreture of UV or gamma waves

There is no such biocide, in fact you must know which kind of pathogen you're having in your sample in order to chose the appropriate biocide. There are biocide for gram positive bacteria and for gram negative ones. What can kill one kind of bacteria can be metabolized for the other. The same thing happen with fungi, there is one kind of fungicide for filamentous fungi and other very different for yeasts, and even within the filamentous ones several species are sensitive to azoles and other ones are resistant.. And think about this, if you want a general biocide to kill every kind of microorganisms then you will damage the organisms you're working with, especially their cell walls, so you have to know what microbial pathogen you're having problems with to chose the biocide... Sorry there is no other way than cultivate it and make tests... Hope this may be usefull for you

Egs providon,chlorhexidine 90% ,alcohol etc,,

Dear Jiri Barta sir,

I am working to design a Eco friendly biocide which rapidly acts on Organisms in Cooling towers and normal water. And yes I want to target the cell wall because if u prevent the cell to cell communication there is no Slime formation which can solve so many issues. So I thought that Destroying the Cell wall can prevents the cell to cell signalling.

I am kind of new to this. so in case  If my question makes you silly please ignore my mistake.

Thanks

Use melanin.It environmental safe and non toxic to us too...

What pathogen is it?  There are several porins that are specific for certain types of pathogens that would otherwise not be all that harmful for humans or other aquatic life.

try with hydrogen peroxide. No biocide could be eco-friendly, of course, the advantage in this case is the rapid transformation into water 

Are you dealing with an elevated temperature in your application for cooling towers?  Biofilms are a very difficult thing to combat.  While many can be broken up by chemicals such as hypochlorite, even in water treatment and delivery systems where it is used in the delivery of water to end users, biofilms form over time.  While they may be disrupted by shocking or raising the level suddenly.  They will return once levels drop.  

Even under harsher conditions, small niches can form where organisms can survive and begin the formation of new films.  From these pockets, films will spread as they setup an environment where organisms within the film are protected from the surrounding milieu.  The problem is complex and easy solutions are unfortunately not particularly environmentally friendly.

While in college I worked at a facility that used water based chillers to cool rooms.  The condensate collected at these coolers supported a combination of bacteria and filamentous mold, which formed a biofilm on the condensation collectors and drain lines.  The method for keeping these clear was 37 degree Celsius or warmer 50% water hypochlorite solution, sprayed monthly over the condenser.  Then the lines were cleared by pouring same solution in collection tray at the same monthly interval.  The biofilm broke down quickly and was flushed out to a collection vessel where it was diluted and disposed to sanitary sewer system.  

While this is not the answer to your situation perhaps, it illustrates the difficulty in maintaining a system where water is either condensed and collected for disposal or used as a coolant.  Both are excellent candidates for and provide excellent environments for biofilm formation.  

I'd like to point out a few things.  First, we don't really know what system Bhagath is using, so it may be necessary for him/her to clarify this. Second, neither hydrogen peroxide nor sodium hypochlorite actually kill microbes by destroying cell walls of bacteria or fungi, yet both are effective antimicrobials.  One of the central issues raised by this question is whether or not pathogen cell walls really need to be destroyed.  In many cases, killing the pathogenic microbes would be sufficient.  If killing pathogens is acceptable AND if the system Bhagath is using allows it, then I'd agree with Donatella Giacosa that using a concentrated solution of hydrogen peroxide (at least 50%, v/v) would be ideal, as long as this is possible in the system Bhagath is using.  The attraction of hydrogen peroxide regarding aquatic exposure or discharge are its nontoxic breakdown products.

I am guessing that the question is about cleaning the inside of a biosafety cabinet, in which case 10% bleach is the standard.  To prevent salt buildup and rust, you can follow that with 70% alcolhol.

Hi Donald,

I recommend to be careful with ethanol or similar volatile solutes in safety cabinets (altough this is not the issue of  Bagath's question): alcohol vapour is highly explosive in the (nearly) closed gas circuit of safety cabinets. In our laboratory, it is explicitly prohibited to use alcohol as surface disinfectant in safety cabinets.

Depending of the water volume and the contstruction of  your container device physical methods can be considered. Heating or microwave treatment in a flowthrouh system may help you. Such methods are environment friendly.

If you are trying to clean the towers then hydrogen peroxide, potassium hydroxide, chlorine dioxide, or peracetic acid may work. However, if you want something that is actually supposed to be added to the water in the cooling tower to prevent microbial growth that is environmentally friendly you are asking the impossible. If it kills microbes it is by definition not environmentally friendly. For water systems things like injecting ozone, which dissipates rapidly, have been used. Other strategies include combining elements at low levels that will be diluted if added to the environment so they will cause less environmental damage i.e. adjusting the pH so that sanitizing agents are more affective.

Try formaldehyde

Another thought comes to mind.  If you are attempting to kill organisms as it appears in a cooling tower or cooling system.  Would it be possible to treat the water with UV?  A number of water treatment facilities are using this alone or combination with H2O2 with success on a wide array of contaminated waters to purify for potable water supplies or industrial/commercial processes.  . The factor is getting sufficient volume through your treatment system with sufficient uv intensity to kill organisms.  Prior to this, cleansing your system of contaminating organisms so treatment would not have to overcome existing contamination.  There would be no residual chemicals because none were added that could pose a threat to the environment.

Ultraviolet light is naturally occurring and in the appropriate wavelengths and intensities to will kill microorganisms through disruption of their DNA.  While you suggested specificity was a goal and targeting of cell-wall was desired, it appeared the goal was prevention of biofilms and growth of organisms.  Here you would only be killing organisms contained in the water of your system.  We used UV C often to inactivate cells in culture (bacterial, fungal, yeast, or human).  You could treat the water as it is pumped up to cascade down the cooling tower if your system is one of such design.

Similarly, most cooling towers pull air through to achieve an evaporative cooling as air passes over water.  The incoming air could be passed through charge plates such as some ionization based purifiers that would draw contaminates in the air to charged plates.  These would require cleaning to remove build up.  Obviously this would be an industrial sized purification system but much easier to clean perhaps than replacing large scale HEPA filters that would remove potential contaminants drawn into the cooling system.  At this point it might be more of an engineering question or problem.  Since your details are somewhat sketchy and it is unclear whether there is a budget or what scale or volume is to be treated, I thought something other than a chemical solution might work.

try hydrogen peroxide