Immobilization of Saccharomyces cerevisiae using polyethyleneimine grafted collagen fibre as support and investigations of its fermentation performance

Abstract

In the present investigation, an collagen fibre (CF), abundant natural biomass, was successfully grafted by polyethyleneimine (PEI). The resultant PEI grafted collagen fibre (CF-PEI) was employed as biocompatible and high cell loading support matrix for the immobilization of Saccharomyces cerevisiae cells. The as-prepared CF-PEI immobilized cells (CF-PEI-cell) exhibited high activity and stability for both batch and continuous fermentation. In batch fermentation, CF-PEI-cells showed enhanced stability as compared with other matrices supported cells, and produced an average ethanol concentration of 45.04 g/L with ethanol yield (Y P/S) of 0.46 g/g and glucose conversion efficiency (h) of 90.4%. Continuous fermentation was operated stably in a down-flow trickling bed reactor charged with CF-PEI-cell for a total of 2 months. When the dilution rate was 0.16 1/h, the average ethanol productivity reached 7.18 g/(L h) with h of 88.94%. Further scanning electron microscopy observations confirmed that yeast cells can proliferate on the surface of CF-PEI during ethanol fermentation, which demonstrates that CF-PEI is indeed an ideal matrix for the immobilization of yeast cells.

Three‐dimensional‐printed millireactor with yeast immobilized in calcium‐alginate film for application in fermentation processes

“…When comparing the systems of Najafpour et al 6 and Zhu et al 9 with that of Seo et al, 10 it is observed that equivalent productivity and efficiency are obtained at the microscale. Seo et al 10 obtained productivity of 5.75 g L −1 h −1 and efficiency of 75%.…”

“…In the macrosystems of Najafpour et al 6 and Zhu et al, 9 despite high efficiency of 88% and 89%, ethanol productivity was 3.8 and 7.2 g L −1 h −1 , respectively. This is due to the residence time of approximately 6 h used by both authors.…”

“…Bangrak, Limtong, and Phisalaphong 8 packed 32% of a column reactor (D = 5.7 cm and L = 43.4 cm) with yeast immobilized in squares of 3% alginate measuring 20 × 20 mm and 3‐mm deep. In these conditions and using a sugar concentration of 220 g L −1 , the authors were able to produce ethanol at a rate of 11.5 g L −1 h −1 , reaching efficiency of 51.06% in a residence time of 5 h. In a down‐flow trickling bed reactor (D = 4 cm, L = 50 cm), 70% packed with yeast immobilized in a matrix of collagen fiber, Zhu et al 9 took 6.25 h to reach efficiency of 88.94% with productivity of 7.18 g L −1 h −1 in continuous fermentation for a glucose concentration of 100 g L −1 . Despite the high efficiency, the productivity of these systems is not expressive due to their high residence time.…”

Yeast immobilisation for brewery fermentation

“…Since the 1970s, various methods for microbial immobilisation have been proposed ( 12,13 ) , and several bioprocesses have been established using immobilised cell technology, such as vinegar production ( 2 ) and wastewater treatment ( 13 ) . In general, there are four recognised methods for whole cell immobilisation, based on the type of interaction between cells and the support.…”

“…The materials used for cell entrapment include polysaccharide gels, such as alginates, κ-carrageenan and chitosan (28)(29)(30)(31)(32)(33). In addition, cellulosic materials, ceramic-like materials and gelatines have also been used (12,32,(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45). The porosity of the material is the most important variable that determines the success or failure of the support.…”