DHAKA - Owners of a Bangladesh garment factory were denied bail on Sunday after surrendering to a court which sought their arrest over the country's worst industrial fire that killed 111 workers.Delwar Hossain and his wife Mahmuda Akter handed themselves in to the magistrates court almost six weeks after it issued warrants for their arrest over the 2012 blaze that gutted the Tazreen factory."The court rejected their bail prayers and sent them to jail," prosecutor Anwarul Kabir told AFP, as more than 100 people protested outside the court to demand the couple's conviction.Although warrants were issued on December 31, police have not arrested Hossain and Akter who have been charged over the tragedy at the factory where workers stitched clothes for Western retailers including Walmart.It was not clear why the couple, who have been been living freely in Dhaka despite the warrants, decided to give themselves up to the court on Sunday.The pair are among 13 people, including factory managers and security guards, charged with arson, culpable homicide not amounting to murder, and death by negligence over the tragedy. All face a maximum sentence of life in prison if convicted. The November 2012 fire, the country's deadliest at a garment factory, highlighted appalling safety problems in the sector, a mainstay of the economy, where about four million workers toil for some of the lowest sector wages in the world.Bangladesh suffered an even greater tragedy just months later in April when the Rana Plaza garment factory complex collapsed in Dhaka's outskirts, killing 1,135 people in one of the world's worst industrial disasters. Police have said it was possibly the first time an owner has been charged over a fire in the sector, where deadly accidents are common. Manufacturers are hugely influential in Bangladesh, where some flout safety rules for the 4,500 garment factories, which account for up to 80 percent of the impoverished country's exports. Hossain, who since the tragedy has been barred from leaving the country, has been accused of breaching construction rules including building unsafe and narrow staircases in the nine-storey building.Victims of the fire, mostly women who were paid as little as $37 a month, found themselves overcome by smoke or were forced to jump from windows on upper floors, police have said.Managers and security guards were charged over their insistence workers return to their duties even though smoke was billowing from the ground floor where the fire started, according to a police investigation report.The factory, in the Ashulia industrial district, supplied clothes to a variety of international brands including US giant Walmart, Dutch retailer C&A and ENYCE, a label owned by US rapper Sean "Diddy" Combs.The industry is the world's second largest after China and factory owners -- many of whom are also lawmakers and owners of banks and insurers -- wield great influence in Bangladesh.Bangladesh pledged to clean up the industry after the Rana Plaza disaster and more than 100 top Western retailers have signed up to new safety agreements to allow greater scrutiny of their operations.The government in December raised minimum wages for workers by 76 percent and launched inspections of factories in the wake of mounting criticism that authorities were failing to improve the sector.The new minimum wage of $68 a month still makes Bangladesh one of the lowest paid garment sectors in the world, according to activists.