How does a gas generating sachet create anaerobic conditions?

A gas generating sachet combines two reactions inside one sealed envelope: it consumes the oxygen already present in the jar and releases carbon dioxide and hydrogen in its place. The oxygen is removed by a chemical absorbent, while the hydrogen produced is combined with the residual oxygen on the surface of a palladium catalyst to form water, which is why a catalyst is essential and why a spent catalyst gives poor growth. Because the reaction starts only when the sachet is exposed to air and moisture, the jar is closed as soon as the sachet is opened, and the indicator strip confirms that the atmosphere inside has actually reached the target conditions.

How often should the palladium catalyst be replaced or regenerated?

Treat the catalyst as a consumable condition, not a permanent fitting. Heat it in an oven in a clean, dry container to drive off moisture and restore reactivity, or replace it when growth becomes inconsistent or the indicator takes noticeably longer to change colour. Moisture is the enemy: a catalyst left in a damp jar or stored with the lid closed while wet loses activity within a few cycles. After every use, dry the jar, remove the catalyst to a dry place, and keep a spare catalyst on hand so a poorly performing one does not stall an incubation. Record the date when each catalyst was last regenerated.

What gas composition do CampyPak sachets produce and when are they used?

CampyPak and similar microaerophilic sachets are formulated to give the reduced oxygen atmosphere that Campylobacter and related organisms need, typically around five to six percent oxygen with a raised carbon dioxide level, rather than the complete absence of oxygen supplied by standard anaerobic sachets. Use them whenever the target organism is described in the method as microaerophilic. Using a full anaerobic sachet for a microaerophilic organism can suppress growth, and using a microaerophilic sachet for a strict anaerobe will not remove enough oxygen. Always confirm with the jar indicator and, where a method is validated, against the supplier's stated gas profile.

What does JWRESEARCH supply for anaerobic culture in Singapore?

JWRESEARCH supplies anaerobic culture systems in Singapore: polycarbonate and glass anaerobic jars in 2.5 litre, 3.5 litre and 7 litre sizes, stainless steel clamp closures and replacement gaskets, standard anaerobic gas generating sachets, microaerophilic sachets for Campylobacter work, palladium and platinum catalysts, anaerobic and microaerophilic indicator strips, and anaerobic workstations for laboratories that need continuous handling rather than batch jars. We also stock anaerobic jars without sachets for laboratories that prefer gas-exchange systems. Tell us the organisms you work with, your incubation volume and the throughput per batch, and we will match the jar, sachet and catalyst.

Anaerobic Jars and Gas-Pak Systems Singapore

Published: {{NEW_ARTICLE_DATE}} | By JWRESEARCH | Category: Laboratory Equipment

An anaerobic jar is a small controlled atmosphere, and it only works if every part of the system agrees with the others: the jar seals, the sachet consumes the oxygen it promises to consume, the catalyst removes what the sachet leaves behind, and the indicator tells the truth about what actually happened inside. Skip one element and the plates still incubate, the colonies still appear, and the result is quietly wrong.

At JW RESEARCH SUPPLY, we supply anaerobic jars, gas generating sachets, catalysts and indicators to clinical, food and research microbiology laboratories across Singapore. This guide covers jar selection, the sachet and catalyst system, and the habits that keep anaerobic work reproducible.

Jars, Workstations and Gas Exchange

Most Singapore laboratories run batch culture in jars, because a jar is inexpensive, simple and easy to validate: load the plates, add a sachet, close the lid, incubate, read. A jar system suits daily plate counts, isolation work and reference cultures. Anaerobic workstations, by contrast, keep a permanently controlled atmosphere and let an analyst work continuously without unsealing a jar for every transfer; they are the right answer when throughput is high or when an isolation depends on exposing plates to air for as little time as possible. A third route, gas exchange with vacuum and a gas mixture, gives the same atmosphere without sachets and is often chosen for long studies or unusual gas profiles. The jar itself is the same in all cases; what changes is how the atmosphere is created and maintained.

Jar Formats Compared

Jar Type	Capacity	Closure	Best For
Compact polycarbonate jar	≈ 2.5 L	Clamp with gasket	Small batches, 6 to 10 plates
Standard polycarbonate jar	≈ 3.5 L	Clamp with gasket	Routine anaerobic plate work
Large polycarbonate jar	≈ 7 L	Clamp with gasket	High plate counts, workshop batches
Glass anaerobic jar	3.5 L to 7 L	Clamp with gasket	Heat stable, easy to clean and see through
Microaerophilic jar system	Matches jar size	Clamp with gasket	Campylobacter and related organisms
Anaerobic workstation	Continuous chamber	Air lock / glove ports	Continuous handling, high throughput

Specification Reference

Parameter	Typical Value	Notes
Working capacity	2.5 L, 3.5 L, 7 L	Plate count depends on plate diameter
Body material	Polycarbonate, polypropylene or borosilicate glass	Polycarbonate is clear and impact resistant
Sealing	Clamp with rubber or silicone gasket	Gasket condition decides the seal
Atmosphere generated	≈ 0 % O₂, 4 to 10 % CO₂	Varies by sachet formulation
Microaerophilic atmosphere	≈ 5 to 6 % O₂ with raised CO₂	For Campylobacter and similar organisms
Catalyst	Palladium or platinum coated pellets	Removes residual H₂ and O₂ as water
Indicator	Resazurin or methylene blue strip	Confirms the atmosphere actually achieved
Incubation	Typically 35 to 37 °C, 24 to 48 h	Follow the method for the organism

Making the Atmosphere Work

Read the sachet instructions for the jar volume you are using, and never stretch a small sachet across a large jar. Open the sachet, place it and the plates in the jar, add the catalyst and an indicator strip, and close the clamp immediately, because the reaction begins as soon as the sachet meets air and moisture. Check the clamp and the gasket before every run: a hardened or twisted gasket is the most common reason a jar fails to reach anaerobic conditions. After incubation, open the jar in a ventilated area, remove the plates, and dry the jar and its parts. The indicator is the record that the atmosphere was right; if it has not changed colour, the run should be repeated rather than reported.

Care of the System

Replace or regenerate the palladium catalyst regularly; moisture destroys activity.
Inspect and replace gaskets before they harden, and keep spares on site.
Dry the jar fully after each use, including the lid recess and catalyst well.
Use an indicator in every run, not just in validation work.
Do not overfill a jar: plates must not crush against the base or the lid.
Match the sachet type to the organism — anaerobic and microaerophilic are not interchangeable.
Record jar, catalyst and sachet lot numbers so a failed run can be traced.

Ordering Checklist

Organisms and whether they are strict anaerobes or microaerophilic
Jar volume and the number of plates per batch
Polycarbonate or glass body, and single or multiple jars
Standard or microaerophilic gas generating sachets, and the pack size
Palladium or platinum catalyst and spare gaskets
Indicator strips, plus a workstation if handling must be continuous

Tell us the organisms you work with, the incubation volume and the number of batches per week, and we will match the jar, sachet, catalyst and indicator that keep your anaerobic results reproducible, with local delivery across Singapore.

Contact JWRESEARCH

JW RESEARCH SUPPLY — laboratory equipment and consumables, Singapore.
Telephone / WhatsApp: +65 8039 3660
Email: SINGAPORE@JWSHY.COM
Website: www.jwresearch.cn