Cofermentation of glucose, xylose, and arabinose is critical for complete bioconversion of lignocellulosic biomass, such as agricultural residues and herbaceous energy crops, to ethanol. We have previously developed a plasmid-bearing strain of Zymomonas mobilis (206C[pZB301]) capable of cofermenting glucose, xylose, and arabinose to ethanol. To enhance its genetic stability, several genomic DNA...

Pyruvate decarboxylase (PDC) is a key enzyme in homoethanol fermentation process, which decarboxylates 2-keto acid pyruvate into acetaldehyde and carbon dioxide. PDC enzymes from potential ethanol-producing bacteria such as Zymomonas mobilis, Zymobacter palmae and Sarcina ventriculi have different K(m) and k(cat) values for the substrate pyruvate at their respective optimum pH. In this study, t...

Biorefinery to produce value-added biochemicals offers a promising alternative meet our sustainable energy and environmental goals. Acetoin is widely used in the food cosmetic industries as taste fragrance enhancer. The generally regarded safe (GRAS) bacterium Zymomonas mobilis produces acetoin an extracellular product under aerobic conditions. In this study, metabolic engineering strategies we...

After being expressed in Escherichia coli JC5412, which is defective in glutamate transport, a Zymomonas mobilis gene which enabled this strain to grow on glutamate was cloned. This gene encodes a protein with 33% amino acid identity to the leucine-responsive regulatory protein (Lrp) of E. coli. Although overall glutamate uptake in E. coli was increased, the protein encoded by the cloned fragme...

Fossil energy is part of the needs people in any country, including Indonesia. The need for fossil increasing day by day. Therefore, efforts were made to find alternative raw materials from non-food sector manufacture ethanol. Cellulose material has potential as an One wastes that can be used Arabica coffee skin. This study aims determine effect concentration crude cellulase enzyme on sugar and...

Cellulosic biomass from agricultural and forestry residues, waste paper and industrial wastes could be used as an ideal and inexpensive source of sugar for sustainable fermentation into transportation fuel. As such, ethanol-producing microorganisms, mainly Zymomonas mobilis and Saccharomyces cerevisiae are potential candidates for ethanol production. However, the substrates are not cost effecti...

Zymomonas mobilis produces two extracellular sucrases namely levansucrase (sac B) and sucrase (sac C). A mutant strain of Z. mobilis CT2 defective in sucrase sac C, constructed earlier by gene disruption, produced higher levels of levan (27.2 g L) than the parent strain B14023 (15.4 g L) from 200 g L of sucrose at 25°C and pH 5.0. Increasing fermentation temperature from 25 to 35°C enhanced eth...