**4. Concluding Remarks and Prospects**

When scientists started working on the valorization of lignocellulosic biomass, different bioprocessing technique such SSF and SMF, CBP emerged to play a critical role in the environment and economy. Scientists are using the genetic engineering method on microorganisms to play all the functions with or without pretreatment. CBP is timesaving and cost-effective in biorefineries as it is a one-process technique involving less instruments or one single reactor. In the future, CBP will play a vital role in converting lignocellulosic biomass to ethanol and other essential products in a single process or reactor with or without pretreatment because of some microorganisms capable of doing all at once, making it more economical and timesaving.

**Author Contributions:** Conceptualization, H.A.R. and R.T.-T.; writing—original draft, E.O.-M. and A.S.; writing—review and editing, H.A.R., R.T-T., E.O.-M., A.S. and R.C.-V.; Project administration, H.A.R. and R.T.-T.; funding acquisition, H.A.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Secretary of Public Education of Mexico–Mexican Science and Technology Council (SEP-CONACYT, Mexico) for the Basic Science Project -2015–01, grant number 254808. Anusuiya Singh also thanks the National Council for Science and Technology (CONACYT, Mexico) for her Ph.D. Fellowship support. Publication funded by "Programa de Fortalecimiento a la Excelencia Educativa" (PROFEXCE-2020).

**Conflicts of Interest:** The authors declare no conflict of interest.
