The Pangi Valley of Chamba, in the Indian western Himalayas, has remarkable biodiversity. Because of its geographic location, it remains relatively undisturbed by humans.
This remote area has been rummaged by researchers from the CSIR-Institute of Himalayan Bioresource Technology, Himachal Pradesh. They were looking for microbes with distinctive properties and stumbled upon several new microbes with unique properties. The microbial strains were tagged as PCH for the Pangi-Chamba Himalaya region. Their goal now was to find a microbe extraordinaire with cellulolytic properties to degrade cellulose from waste rice grains for commercial use.
The team first screened for cellulolytic bacteria by growing the strains on media containing cellulose as sole carbon source. They isolated more than 60 different strains of bacteria that showed cellulolytic properties under different temperatures and pH. They focussed on five strains with high cellulolytic activity. Of the five, Bacillus sp. PCH94 had the highest cellulolytic activity.
And – surprise, surprise – the bacteria from the cold mountainous terrain grew best at a high temperature of 50-degree Celsius! The strain adapted easily to a broad range of pH, too.
“We’d found heat-loving bacteria, thermophiles, in that cold environmental niche,” says Dharam Singh, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT).
Now that the team had established that the bacterium could degrade complex celluloses, they optimized the nutrients needed to degrade cellulose from rice grains. They identified apt concentrations of low-cost substrates that increased the activity of the bacteria two-fold.
The researchers sequenced the whole genome of Bacillus sp. PCH94. They found that this bacterium had sequences that could produce a variety of lignocellulolytic enzymes – enzymes that break lignin and cellulose, substances that are abundant in plants.
The bacteria had high cellulase activity and a much faster production time of only 9 hours.
“Other bacteria took around 2 to 3 days for the same results”, says Vikas Thakur, CSIR-IHBT. “This bacterium could digest various cellulose sources – filter paper, starch, …”
Commercially, cellulose materials are degraded using chemicals that are harmful or costly enzymes. The researchers compared the cellulolytic activity of the bacteria with two commercial cellulases and found that the bacterial activity was superior.
“The thermophilic bacterium can be useful in paper and biofuel industries where high temperature effluents with cellulose pose a problem”, says Sanjay Kumar, CSIR-IHBT.
K Sri Manjari
University College for Women, Osmania University
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