I was wondering whether there are hypotheses that take a different approach that is contrary to the heterotroph hypothesis. The heterotroph hypothesis states that autotrophs evolved from heterotrophs because of the lack of food. Is this issue still debated by scientists or is the heterotroph universally accepted?
I would say the the topic is still very much under debate. This paper by Ferry and House (2006) briefly review the heterotrophic vs chemoautotrophic hypotheses. They include citations from proponents of each hypothesis. Interestingly, Ferry and House propose an "energy conservation" hypothesis that attempts to merge ideas from the other two hypotheses. Overall, much work remains to be accomplished in this field before we have a clear understanding of the origins of life.
Ferry, J.G. and C.H. House. 2006. The stepwise evolution of early life driven by energy conservation. Molecular Biology and Evolution 23: 1286-1292.