New concept for conversion of lignocellulose to ethanol and furfural.

Studies on the chemical mechanisms of furfural formation showed the possibility to apply a new differential catalysis of hemicellulose - its depolymerisation and pentose dehydration to furfural. This change led to the increase in furfural yield and essential decrease of cellulose destruction. The lignocellulose residue that remains after the production of furfural may be subjected to enzymatic hydrolysis to glucose and the subsequent fermentation to ethanol.

Changes in Energy Status of Cells during Dehydration and Rehydration.

Anhydrobiosis is the state of life when cells are exposed to waterless conditions and gradually cease their metabolism. In this study, we determined the sequence of events in energy metabolism during processes of dehydration and rehydration. The intensities of respiration and acidification of the medium, the amounts of phenyldicarbaundecaborane (PCB) bound to yeast membranes, and the capabilities of cells to accumulate K were assayed using an electrochemical monitoring system, and the intracellular content of ATP was measured using a bioluminescence assay.

Engineering of sugar transporters for improvement of xylose utilization during high-temperature alcoholic fermentation in Ogataea polymorpha yeast.

Background: Xylose transport is one of the bottlenecks in the conversion of lignocellulosic biomass to ethanol. Xylose consumption by the wild-type strains of xylose-utilizing yeasts occurs once glucose is depleted resulting in a long fermentation process and overall slow and incomplete conversion of sugars liberated from lignocellulosic hydrolysates. Therefore, the engineering of endogenous transporters for the facilitation of glucose-xylose co-consumption is an important prerequisite for efficient ethanol production from lignocellulosic hydrolysates.

Microbial lag phase can be indicative of, or independent from, cellular stress.

Measures of microbial growth, used as indicators of cellular stress, are sometimes quantified at a single time-point. In reality, these measurements are compound representations of length of lag, exponential growth-rate, and other factors. Here, we investigate whether length of lag phase can act as a proxy for stress, using  a number of model systems (Aspergillus penicillioides; Bacillus subtilis; Escherichia coli; Eurotium amstelodami, E.

Anhydrobiosis in yeasts: Glutathione synthesis by yeast Ogataea (Hansenula) polymorpha cells after their dehydration-rehydration.

The possibility of using active dry microbial preparations in biotechnological processes is essential for the development of new modern industrial technologies. In this study, we show the possibility of obtaining such preparations of the genetically engineered yeast strain Ogataea (Hansenula) polymorpha with glutathione overproduction. Special pre-treatment involving the gradual rehydration of dry cells in water vapour led to the restoration/reactivation of almost 100% of dehydrated cells.

Anhydrobiosis in yeasts: Psychrotolerant yeasts are highly resistant to dehydration.

Yeast cells are able to transition into a state of anhydrobiosis (temporary reversible suspension of metabolism) under conditions of desiccation. One of the most efficient approaches for understanding the mechanisms underlying resistance to dehydration-rehydration is to identify yeasts, which are stable under such treatments, and compare them with moderately resistant species and strains. In the current study, we investigated the resistance to dehydration-rehydration of six psychrotolerant yeast strains belonging to two species.

Resistance of a recombinant Escherichia coli to dehydration.

Dehydration of microorganisms, rendering them anhydrobiotic, is often an efficient method for the short and long term conservation of different strain-producers. However, some biotechnologically important recombinant bacterial strains are extremely sensitive to conventional treatment. We describe appropriate conditions during dehydration of the recombinant Escherichia coli strain HB 101 (GAPDH) that can result dry cells having a approximately 88% viability on rehydration.