Cellulosic ethanol is well established as an excellent additive to gasoline with reduced carbon release. Although various biomass process technologies have been implemented to enhance biomass saccharification, lignocellulose recalcitrance leads to process difficulties for a cost-effective and environmental friendly bioethanol production. It thus remains essential to address several fundamental issues: (1) What are the key factors of lignocellulose recalcitrance that need be reduced by optimal pretreatments? (2) Is there a universal standard that could judge optimal pretreatment? (3) How could desirable lignocellulose substrate be combined with the optimal pretreatment to acquire maximum bioethanol yield? In this lecture, therefore, we will describe the main factors of lignocellulose recalcitrance that could be significantly reduced for much-increased biomass porosity in the pretreated biomass residues. Notably, this lecture will briefly tell a story about a fundamental cell wall structure that may occur in plant kingdoms, leading to proposing a mechanism model about the unique breakpoints of native cellulose microfibrils that could provide an applicable strategy for optimal biomass process technology in bioenergy crops.