Maximization of the bioethanol concentration produced through the cardboard waste fermentation by using ethylenediamine-modifying poly(acrylonitrile-co-methyl acrylate) membrane

In the current research, cardboard waste was used as raw material for the production of bioethanol. Physical, chemical, and enzymatic treatments were used to enhance the glucose production from cardboard waste through the prehydrolysis process. The obtained results revealed the maximum production of 1.40575 mg/ml of glucose units when the cardboard waste was treated with 20% HCl and hot plating. Using the same conditions followed by cellulase enzyme treatment increased the glucose concentration up to 2.78913 mg/ml. However, the sole use of the cellulase enzyme for the hydrolysis process resulted in more glucose concentration of 10.95846 mg/ml. The yeast isolate T1 succeeded to produce 2.93489 mg/ml bioethanol when using glucose produced from the cardboard waste hydrolysis as a raw fermentation source. The genetic identification of the yeast showed 98% similarity to Pichia nakasei, and its amplified 18S rRNA gene sequence was submitted in GenBank through the accession number OK092294. On the other hand, poly(acrylonitrile-co-methyl acrylate) modified with ethylenediamine (EDA) membrane was prepared to be applied in the purification of the produced bioethanol using Amicon cell ultrafiltration system. The prepared membrane was characterized through scanning electron microscope (SEM), Fourier transform infrared (FTIR), Raman spectroscopy, water contact angle measurement, and water and ethanol uptake. The separation processes showed that the best ethanol concentration and flux of permeate were obtained under nitrogen pressure 40 psi as 4.01587 mg/ml and 950.608 (mg/m2.h), respectively, for the yeast produced bioethanol. The obtained results revealed that the system of Amicon cell integrated with poly(AN-co-MA) modified with EDA membrane succeeded to increase the bioethanol concentration from 0.293 to 0.40% with a total flux of permeate 2698.447 (mg/m2.h), in addition to its ability to increase the concentration of the laboratory-prepared ethanol/water mixture from 25 to 42.5%.