Aims: To determine acetic acid, acetaldehyde and glycerol production by wine yeast throughout Icewine fermentation. The expression of yeast cytosolic aldehyde dehydrogenases (ALD3 and ALD6) and glycerol-3-phosphate dehydrogenase (GPD1) were followed to relate metabolites in the wines to expression patterns of these genes. Methods and Results: Icewine juice (38AE8°Brix, 401 ± 7 g l )1 sugar), diluted Icewine juice (21AE3°Brix, 211 ± 7 g l )1 sugar) and the diluted juice with sugar levels equal to the original Icewine juice (35AE6°Brix, 402 ± 6 g l )1 sugar) were fermented in triplicate using the commercial wine yeast K1-V1116. Acetic acid production increased 7AE1-fold and glycerol production increased 1AE8-fold in the Icewine fermentation over that found in the diluted juice fermentation. ALD3 showed a 6AE2-fold induction and GPD1 showed a 2AE5-fold induction during Icewine vs the diluted fermentation. ALD3 was not glucose repressed when additional sugar was added to diluted juice, but was upregulated 7AE0-fold. Conclusions:The NAD + -dependant aldehyde dehydrogenase encoded by ALD3 appears to contribute to acetic acid production during Icewine fermentation. Expression of GPD1 was upregulated in high sugar fermentations and reflects the elevated levels of glycerol. Solutes in Icewine juice in addition to sugar contribute to the yeast metabolic response. Significance and Impact of the Study: This work represents the first descriptive analysis of the fermentation of Canadian Icewine, the expression patterns of yeast genes involved in metabolite production, and their impact on Icewine quality. A role for ALD3 in acetic acid production during Icewine fermentation was found.

Allogeneic cell therapy products are generating encouraging clinical and pre-clinical results. Pluripotent stem cell (PSC) derived therapies, in particular, have substantial momentum and the potential to serve as treatments for a wide range of indications. Many of these therapies are also expected to have large market sizes and require cell doses of ≥109 cells. As therapeutic technologies mature, it is essential for the cell manufacturing industry to correspondingly develop to adequately support commercial scale production. To that end, there is much that can be learned and adapted from traditional manufacturing fields. In this review, we highlight key areas of allogeneic cell therapy manufacturing, identify current gaps, and discuss strategies for integrating new solutions. It is anticipated that cell therapy scale-up manufacturing solutions will need to generate batches of up to 2,000 L in single-use disposable formats, which constrains selection of currently available upstream hardware. Suitable downstream hardware is even more limited as processing solutions from the biopharmaceutical field are often not compatible with the unique requirements of cell therapy products. The advancement of therapeutic cell manufacturing processes to date has largely been developed with a cell biology driven approach, which is essential in early development. However, for truly robust and standardized production in a maturing field, a highly controlled manufacturing engineering strategy must be employed, with the implementation of automation, process monitoring and control to increase batch consistency and efficiency.

Aims: We previously reported that the aldehyde dehydrogenase encoded by ALD3 but not ALD6 was responsible, in part, for the increased acetic acid found in Icewines based on the expression profile of these genes during fermentation. We have now completed the expression profile of the remaining yeast aldehyde dehydrogenase genes ALD2, ALD4 and ALD5 during these fermentations to determine their contribution to acetic acid production. The contribution of acetaldehyde stress as a signal to stimulate ALD expression during these fermentations was investigated for all ALD genes. The expression of glycerol-3-phosphate encoded by GPD2 was also followed during these fermentations to determine its role in addition to the role we already identified for GPD1 in the elevated glycerol produced during Icewine fermentation. Methods and Results: Icewine juice (38AE5°Brix, 398 ± 5 g l )1 sugar), dilutedIcewine juice (20AE8°Brix, 196 ± 4 g l )1 sugar) and the diluted juice with sugar levels equal to the original Icewine juice (36AE6°Brix, 395 ± 6 g l )1 sugar) were fermented in duplicate using the commercial wine yeast K1-V1116. Acetic acid and glycerol production increased 8AE4-and 2AE7-fold in the Icewine vs the diluted juice fermentation, respectively, accompanied by a fourfold transient increase in acetaldehyde in the Icewine condition during the first week. Both mitochondrial aldehyde dehydrogenases encoded by ALD4 and ALD5 were expressed, with ALD5 expression highest at the start of all fermentations and ALD4 expression increasing during the first week of each condition. ALD2, ALD4, ALD5 and GPD2 showed no differential expression between the three fermentation conditions indicating their lack of involvement in elevating acetic acid and glycerol in Icewine. When yeast fermenting the diluted fermentation was exposed to exogenous acetaldehyde, the transient spike in acetaldehyde increased the expression of ALD3 but this response alone was not sufficient to cause an increase in acetic acid. Expression of the other aldehyde dehydrogenases was unaffected by the acetaldehyde addition. Conclusions: The aldehyde dehydrogenases encoded by ALD2, ALD4 and ALD5 do not contribute to the elevated acetic acid production during Icewine fermentation. Expression of GPD2 was not upregulated in high sugar fermentations and does not reflect the elevated levels of glycerol found in these wines. Acetaldehyde at a concentration produced during Icewine fermentation stimulates the expression of ALD3, but has no impact on the expression of ALD2, -4, -5 and -6. Upregulation of ALD3 alone in the dilute fermentation is not sufficient to increase acetic acid in wine and requires additional responses found in cells under hyperosmotic stress.

Aims: The objective of this study was to determine the effect of increasing juice soluble solids above 40°Brix on wine yeast's ability to grow and ferment the juice, with particular focus on acetic acid production, titratable acidity (TA) changes and the maximum amount of sugar consumed by the yeast. Methods and Results: Riesling Icewine juices at 40, 42, 44 and 46°Brix were inoculated with K1-V1116 at 0AE5 g l )1 and fermented at 17°C until sugar consumption ceased. Increasing soluble solids showed strong negative linear correlations with yeast growth, sugar consumption and ethanol production (r = )0AE999, )0AE997 and )0AE984, P < 0AE001, respectively). Acetic acid, glycerol and TA production normalized to sugar consumed showed strong positive correlations to the initial juice concentration (r = 0AE992, 0AE963 and 0AE937, P < 0AE001, respectively) but no correlation was found for ethanol production. The acetic acid produced as a function of sugar consumed was positively correlated to the glycerol produced (r = 0AE970, P < 0AE001). The final TA of the wines ranged between 11AE8 and 13AE7 g l )1 tartaric acid, increasing by 2AE3-3 g l )1 over the starting juice. The increase in TA was positively correlated to the increase in acetic acid produced after normalizing the data to the amount of sugar consumed (r = 0AE975, P < 0AE001). The acid equivalents resulting from the increase in acetic acid accounted for 80-100% of the TA increase when converted to units of tartaric acid. In the final Icewines, acetic acid represented 19-20% of wine TA. Conclusions: Increasing Icewine juice concentration from 40 to 46°Brix increases the proportion of yeast sugar metabolism towards glycerol and acetic acid production to cope with the increased osmotic stress by decreasing yeast growth, sugar consumption rate, the total amount of sugar consumed and the total amount of ethanol produced. The high proportional contribution of acetic acid to titratable acidity in Riesling Icewine may affect acidity perception. Significance and Impact of the Study: We have determined that 10% v ⁄ v ethanol would not be achievable with initial juice concentrations above 42°Brix and that Riesling Icewine juice above 52AE5°Brix would be theoretically unfermentable. The high proportional contribution of acetic acid to TA may be an important factor in the organoleptic balance of these Icewines.