General query on accounts

We are a partnership firm. It was started in 01.04.2016. During the last two months the one of the partner has spent from his personal account approx. 9,00,000/- for meeting partnership firm expenses as the Income from business is presently very low. Now we have a question in mind. Is it mandatory at this stage to pay Interest on loan to the partner. When we asked the partner he refused to take interest on loan on the plea since there is no income from business he will not take any interest on loan given by him to the partnership firm. Please advise whether its is at the discretion of the partner to take interest on loan or not or it is mandatory the interest on loan to be given to Partner. In case it is mandatory, shall we transfer this interest to Partner Current account.Please clarify.