Hi Lusaka, I just watched your "sinisambol"bun making video. To your question as an alternative to yeast, you can use half and half of lemon juice lemon juice and baking powder.
Oyage hama video ekakma mam balanawa. Mam lankawedi nam mam hama dema hadanawa. Eth dan mam inne ඊශ්රායල් wala.mam hadana videhatamai oyage hama kemakma.❤❤❤❤