The fungus, Trichoderma reesei has long been recognized for its ability to produce large amounts of cellulase enzymes (the enzyme commonly used for cellulose ethanol production). Difficulties in improving Trichoderma reesei for even higher levels of cellulase production stem from the perception that the fungus exhibits an asexual mode of reproduction. "Under the assumption that Trichoderma reesei was asexual, scientists looking to improve the fungus were instead limited to techniques like dosing the fungus with radiation or chemicals in order to alter its genetic profile." This, however, only created random or unpredictable mutations. In contrast, sexual microorganisms are reportedly easier to manipulate artificially for genetic improvement, due to inherent exchange and mix of genetic material. Scientists from the Vienna University of Technology (Austria) have found evidence to show that Trichoderma reesei was genetically identical to another species of fungus, Hypocrea jecorina, which happens to be capable of sexual reproduction." The main difference between the two organisms was that "Hypocrea jecorina seemed capable of assuming both the male and female roles, whereas Trichoderma reesei seemed only capable of assuming the male role." Trichoderma reesei was shown to have the possibility for sexual reproduction. The scientists believe that the findings might lead to better and more cost-effective ways of making biofuels thru cheaper and better cellulases from improved "sexual" Trichoderma strains. Details of the study are published in the Proceedings of the National Academy of Sciences (PNAS) (URL above)..