<p>[PROBLEMS] To provide a bioalcohol and/or a biodegradable plastic at a low cost by ensuring the production of a biomass, which is usable as the starting material of the bioalcohol, at a low cost in an appropriate timing and an appropriate amount. [MEANS FOR SOLVING PROBLEMS] The production of a biomass and the production of a bioalcohol are consistently conducted in a single plant so that the starting materials can be stably supplied and the wastes and the by-products can be recovered and reused. It is also intended to reduce the production cost of the bioalcohol and/or the biodegradable plastic by reusing the heat thus generated.</p>
