Ghana international Essien is keen to join Chelsea but Aulas does not want to sell.
Earlier, Aulas told reporters that he had received a lucrative offer from the English champions but was hoping he could convince Essien to stay in France.
"It's difficult to resist but Michael is not for sale," Aulas
"We will do everything to keep him."
Essien said he wanted a move to the Premier League.
"I want to leave," the player was quoted as saying by French sports daily L'Equipe. "I want to play in England at Chelsea."
Reports in the British media said Essien would be in London for a medical on Tuesday but reporters spotted him in Lyon.
Lyon are due to leave for South Korea on Wednesday to play in the Peace Cup tournament.
Essien told L'Equipe he would not go but Aulas said the player would travel with the team.
"He will come with us and I'll take him to the plane," Aulas said. Manager Houllier added: "He will come with us to Korea."