Salt-loving plants in Pakistan 'potential biofuel sources'
A team of scientists led by Ajmal Khan, director of the Institute for Sustainable Halophyte Utilization at the University of Karachi, has identified several salt-loving grasses such as Halopyrum mucronatum, Desmostachya bipinnata, Phragmites karka, Typha domingensis and Panicum turgidum, whose stems, branches and leaves can be fermented into alcohol. Their findings will be published in an upcoming issue of the Journal of Biomass and Bioenergy.
These 'halophytes' grow quickly throughout the year in saline soils, inland and coastal marshes, and deserts. They do not need fresh sowing every year, or fertilisers and pesticides; are hardy, and produce good quality biomass.
Pakistan has about 410 known salt-loving plants, and some can also replace wheat and maize straw in cattle feed.
"These plants do not compete for good quality water and productive farmlands. They can be potentially used to produce large amounts of biomass while grown with brackish water on saline land, without competing with conventional agriculture," Khan told SciDev.Net. "They could also help reduce carbon dioxide emissions by absorbing carbon dioxide to make food."
Khan said the soluble sugars and some of the woody tissues in these plants could be converted into alcohol. "Our candidate species may be able to produce more than 55 per cent of the biomass for alcohol. Our estimates are that we can produce about 70,000 kilograms of biomass per hectare annually - or 70,000 litres of alcohol per hectare can be obtained annually," he said.
Khan's team recommended that the Pakistan government set up incubation to study the feasibility of wider application, and save some of the USD3.1 billion the country spends each year on petroleum imports.
However, a major drawback is the high cost of biofuel production from these plants. The scientists did not give precise comparisons with costs for conventional fossil fuel petrol.
Non-food biofuel plants also need increased investment in national research in the sector and promotion among potential investors, said Arif Alauddin, chief executive officer of the government's Alternative Energy Development Board, which promotes use of energy sources such as wind, biogas and solar energy.