If Muslim woman dies and does not have the Mahram with her who is going to bury her?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

There is no harm for a woman to be buried by marriageable men whether or not she had Mahaarim (non-marriageable relatives). Anas narrated: "We were present when the daughter of the Prophet was buried. The Prophet had tears flowing downs his cheeks and he asked: "Is there anyone amongst you who did not have sexual intercourse with his wife tonight? So, Abu Talhah replied: 'I did not, O Prophet of Allaah!' So, the Prophet ordered him to get down in her grave and bury her." [Al-Bukhari] However, Imaam Ahmad reported the narration with a different wording: "When Ruqyah died, the Prophet said: "A man who had sexual intercourse with his wife should not enter her grave." So, 'Uthmaan did not enter her grave and he was her husband, and the Prophet who was her father did not enter her grave. It was Talhah who was a marriageable man to her who buried her.

The Fiqh Encyclopaedia reads: "However, the majority of the jurists are of the view that a woman's Mahaarim (non-marriageable relatives) are more appropriate to bury her. When Zaynab bint Jahsh died, 'Umar said: "I sent to women asking them to send someone who may enter her grave. So, the women sent someone who used to enter to her when she was alive [i.e. one of her Mahaarim]. I was convinced that they were truthful."

Furthermore, when the wife of 'Umar died, he said to her family: "You are more deserving [than myself] in burying her."

Allaah Knows best.