* Biofuel mix in one engine on Frankfurt-Hamburg route
* Lufthansa says 6-month trial will save 1,500 tonnes CO2
* Campaigners concerned over impact on land use
(Adds more passenger comment, background on emissions)
FRANKFURT, July 15 (Reuters) - Lufthansa became the first airline to use biofuels on regular commercial flights on Friday in a six month trial that it estimates will reduce CO2 emissions by up to 1,500 tonnes during the period.
European airlines are pressing ahead with biofuel plans in order to cut use of regular jet fuel. A pact signed last month with biofuel producers and the EU Commission aims to produce 2 million tonnes of biofuel for aviation by 2020.
Lufthansa is using a mix of regular fuel and biofuel made by Neste Oil from jatropha and camelina crops and animal fats, in one engine of an Airbus plane on daily flights between Frankfurt and Hamburg.
It said on Friday the aim of the trial, along with reducing emissions, was to examine the effects of biofuel on engines.
Passengers on the flights will not see, feel or hear any difference in the aircraft, Lufthansa biofuels director Joachim Buse told Reuters at the Paris Air Show in June.
Robert Wall, international editor at Aviation Week and a passenger on the first bio-fuelled flight, said the plane departed from Hamburg to a water cannon salute.
"Niko Pointner, the LH A321 captain, said everything was completely normal," Wall said, adding the captain had told passengers Friday's inaugural flight was expected to save 1 metric tonne of CO2.
Transport services provided by Lufthansa released 26.6 million tonnes of CO2 in 2010, according to its annual report. The group plans to reduce emissions per passenger-kilometre by 25 percent by 2020.
Air France-KLM and Britain's Thomson Airways have said they will run commercial flights starting from September using a biofuel mix made from used cooking oil.
However, biofuels are the subject of much debate as to how 'green' they actually are, with the use of crops such as palm oil coming under fire for using land that could instead be used to grow crops to feed people.
Friends of the Earth Europe campaigner Robbie Blake told Reuters that even though Lufthansa now seemed to be avoiding palm oil, there were still concerns over jatropha.
"Switching from palm oil to jatropha is no alternative - this is a crop that is responsible for large-scale land grabbing in Africa, displacing local communities and destroying their livelihoods, with no evidence of a reduction in carbon," he said.
Lufthansa said the production of its biofuel was not in direct competition with food production and no rainforests were destroyed.
Other options for creating biofuel include waste and algae. British Airways is hoping to start powering its fleet using a fuel derived from waste by 2015, but algae is still in the early stages of development, with many predicting it will be at least 10 years before it can be brought into production. (Reporting by Victoria Bryan. Editing by Jane Merriman and Jon Loades-Carter)