Sugar degradation during autoclaving: Effects of duration and solution volume on breakdown of glucose

Abstract

1995. Sugar degradation during autoclaving: Effects of duration and solution volume on breakdown of glucose. -Physiol. Plant. 94: 415^18.As the autoclaving of a sugar together with other nutrient components enhances its degradation with the associated formation of toxic products, it is advisable to autoclave it separately from other medium components. In such cases, and to prepare growth media of consistent quality, it may also be necessary to adjust the duration of autoclaving according to the volume of the sugar solution. The results of an attempt to fine-adjus! the autoclaving procedure are presented. Glucose, used as model .sugar in this investigation, was autoclaved for 20,32 or 44 min in volumes of 0.25. 1,2 and 5 1. The rise in temperature of the solutions was monitored by thermocouples. Glucose degradation was estimated by the rate of cyanide-initiated oxygen consumption. The rates were found to be inversely proportional to the volumes in a semilogarithmic plot. The T-t (temperature-time) value, the area under the solution temperature vs time curve, was found to be an independent variable from which the extent of glucose degradation could be deduced. For a chosen level of thermodegradation of glucose, the duration of autoclaving for solutions of different volumes could be determined graphically from a T-t value vs time plot.

Examining the interaction of light, nutrients and carbohydrates on seed germination and early seedling development of Bletia purpurea (Orchidaceae)

“…In experiment 2, increasing sucrose molarity from 10 to 50 mmol resulted in decreased germination and development. This indicates either that seeds experienced osmotic stress at the higher molarity or that growth and development was inhibited by byproducts of sucrose hydrolysis during autoclaving (Pan and van Staden 1999;Sawyer and Hsiao 1992;Schenk et al 1991;Wang and Hsiao 1995). Byproduct inhibition seems more likely since in experiment 3, where carbohydrates were filter sterilized, germination was not inhibited and seedling development was more advanced in the presence of 50 mmol sucrose compared to 10 mmol treatments.…”

The impact of supplemental carbon sources on Arabidopsis thaliana growth, chlorophyll content and anthocyanin accumulation

“…All supplemental carbon sources (Sigma-Aldrich, St Louis, MO) were added from filter-sterilized stock solutions to ensure that there was no alteration to sugar composition or concentration as a result of autoclaving (Khuri and Moorby 1995;Wang and Hsiao 1995). Maintenance of precise supplemental carbon source concentration ensured that media were iso-osmotic within a concentration.…”

Liquid Hot Water Pretreatment and Enzymatic Hydrolysis as a Valorization Route of Italian Green Pepper Waste to Delivery Free Sugars

“…On the one hand, the fact of finding glucose in the liquid fraction, even under conditions of smoother pretreatments, suggests that glucose could come from another source more easily soluble than cellulose. On the other hand, glucose could constitute an important sugar of the hemicellulosic component and could be released from this component [ 70 ]. In addition, the fact that the values are different under diverse operating conditions supports this hypothesis.…”

“…However, in this case, some additional experimentation would be performed in order to analyze the degradation of these sugars under severe operating conditions. It is important to highlight that it is impossible to have zero sugar degradation at the analyzed operating temperatures when sugar release comes from soluble sugars (glucose and xylose) [ 70 , 71 , 72 ]. Xylose is especially sensitive.…”