29:T474,

This study investigates the clarification of Citrus limetta (sweet lime) juice using a packed bed system incorporating polyvinyl alcohol (PVA)-alginate immobilized pectinase. Free pectinase, though widely used in juice clarification, suffers from drawbacks such as instability, loss of activity, and lack of reusability. To overcome these limitations, pectinase was immobilized via entrapment in a PVA-alginate matrix, forming stable enzyme beads. The immobilized enzyme was characterized for its optimal pH, temperature, incubation time, and reusability. The results indicated that the immobilized pectinase exhibited maximum activity at pH 5 and 40°C, with optimal incubation at 60 minutes. The reusability study showed significant 58% enzymatic activity retention for up to three cycles. Application of immobilized pectinase in a packed bed column demonstrated effective juice clarification of 37%, with a marked reduction in turbidity. The developed system provides a cost-effective and efficient approach for industrial fruit juice processing, enhancing clarity and stability while enabling enzyme reusability.

2a:T54d,

Strong mineral acids such as sulfuric acid are still mainly used to break down carbohydrates in processes that prepare plant-based waste for further use. However, researchers are increasingly studying the use of organic acids as alternatives. This study aimed to obtain organic compounds by fermenting a hemicellulosic extract rich in simple sugars from the organic acid pretreatment of brewer’ spent grain. Hydrolysis tests using 4.5% oxalic acid for 24 minutes at 125.6°C dissolved over 99% of the hemicellulose, producing 14.9 g/L of xylose and 4.9 g/L of glucose. The production of inhibitory compounds was relatively low (0.05 g/L and 0.12 g/L of 5-hydroxymethylfurfural and furfural, respectively), which is beneficial for the yeast’s performance during the next step. The extract was then fermented by three strains of Saccharomyces cerevisiae: one industrial strain (PE-2) and two genetically modified strains (MP-P5 and JDY-01). Despite the hydrolysate containing around 45 g/L of oxalic acid, which significantly inhibited yeast activity in producing ethanol, for example, the three strains still produced several important volatile organic compounds, including 2-phenylethanol, known for its antimicrobial properties, and 4-hydroxy-2-methylacetophenone, a phenolic compound with antioxidant and antiseptic properties.

2b:T4b1,

There is increasing demand for microbial lipids as a sustainable alternative to mitigate the detrimental environmental and societal impacts associated with the production of palm oil, including tropical deforestation, significant contributions to global warming, and extensive land and water use. Microbial lipid production has the potential to address these concerns and meet the growing demand for palm oil through strain engineering and innovative fermentation and downstream process development. However, the current cost to produce microbial oils is not competitive with traditional sources of palm oil, and improvements in fermentation titer, rate, and yield are needed. We report here the application of Adaptive Laboratory Evolution to improve lipid production by the oleaginous yeast Rhodosporidium toruloides, multi-omic characterization of the genome-wide metabolic rewiring resulting from its evolutionary adaptation, and scale-up of a high-cell density fed-batch fermentation process to 50 m³ commercial scale. The methods, strains, and process improvements described here represent significant steps toward commercialization of a fermentation-based palm oil substitute.

2c:T5f4,