The notion that the idea of nature is not quite the unbiased rule to design sustainable futures is obvious. But, nevertheless, questions about nature, how it functions and what it might aim at, is leading the controversial debates about both sustainability and biotechnology. These two research areas hardly have the same theory background. Whereas in the first concept, the idea of eternal cyclical processes is basic, the latter focuses on optimization. However, both concepts can work together, but only under a narrow range of public acceptance in Europe. The plausibility of arguments for using biotechnology within sustainable technologies varies according to the assumed part nature itself plays for reaching optimized states. The culture related vision of nature's functions has impact on agricultural biotechnology, dealing not only with food crops but also with non-food plants like renewable resources that are used for energy or fiber production. These plants are grown to reach sustainable development. However, there is a fundamental difference between regarding biofuels as ``renewable'' and ``regenerative,'' due to the tension between the concepts of ``the natural'' and ``the sustainable.'' Arguments of optimization, efficiency, and efficacy are critically discussed in order to take the present need for sustainable technologies for serious.