2)Mention the condition required for combustion.
Answers-
1) supply of oxygen
2) combustible substances
3) ignition temperature
Answers
Answer: All of the above conditions are essential for combustion ...
Step-by-step explanation: (1) The supply of oxygen is also necessary for combustion...
(2) the presence of combustible substance is necessary for combustion to take place. It is actually the food for fire. the most common supporter is air for combustion.
(3) The lowest temperature at which a substance catches fire and starts burning is called ignition temperature. it is necessary to heat a combustible substance to its ignition temperature so that it may undergo combustion.
HOPE IT HELPS YOU!!!
PLZ MARK IT AS BRAINLIEST!!!
Answer:
Oxygen supply is known to have an important influence on aerobic amino acids production by microorganisms [45], as those aerobic microorganisms generally require large amount of oxygen to reoxidize NAD(P)H2 or FADH2 to effectively generate ATP for metabolism [46,47]. Dissolved oxygen (DO) is an important factor that significantly influences metabolism, biomass synthesis, electron transport, ATP availability, and product yield of C. glutamicum when it expresses recombinant protein in a bioreactor [48]. Oxygen is an indispensable raw material that must be supplied in large amounts in industrial l-arginine production [20,26]. The DO concentration or oxygen supply profile was also reported as one of the crucial factors in optimally regulating metabolic distribution or activities in l-arginine fermentation processes [26].
The metabolic flux analysis has been applied for batch fermentation process with C. crenatum SYPA 5-5 to explore the optimal oxygen supply strategy aiming to achieve the maximum l-arginine production [26]. Based on the results of the metabolic flux analysis [49], a two-stage oxygen supply strategy was proposed and successfully utilized in the enhanced l-arginine production. To better understand the effect of DO levels on batch l-arginine fermentation, the fermentation was divided into four phases, each corresponding to a particular physiological state. Phase I (0–21 h) is the exponential growth phase. All of the nutrients were consumed for bacterial growth and almost no l-arginine was produced in this phase. In phase II (21–45 h), rates of l-arginine secretion and glucose consumption began to increase while cells growth tended to cease. In phase III (45–69 h), l-arginine synthesis rate dropped rapidly to a stable level after reaching a maximum level. Several by-products such as l-isoleucine, lysine, and threonine also began to accumulate during this phase. Phase IV (69–87 h) is the decay phase, and during the phase cells concentration began to decrease.
Three different oxygen supply methods, by controlling agitation rate at 200, 400, and 600 rpm, were classified as low oxygen supply level, medium oxygen supply (MOS) level, and high oxygen supply (HOS) level. It has been found that, during 42–84 h (late fermentation phases), l-arginine production rate under MOS was much more stable than that under HOS, and l-arginine production rate under HOS condition dropped rapidly. This suggested that HOS level in later fermentation phases is not beneficial to the l-arginine production. In addition, the highest dry cells weight (DCW) when fermentation entering into phase II was actually achieved under MOS condition. This is to say, high rates in cells growth and initial l-arginine synthesis achieved by HOS condition during early stage, as well as the high/stable l-arginine synthesis rate achieved by MOS condition during late fermentation stages, seem to be the best operational combination in enhancing the overall l-arginine fermentation performance.
Thus, a two-stage oxygen supply strategy (NOS) was proposed and used in the subsequent fermentation: controlling agitation at 600 rpm during the first 24 h of the fermentation to keep HOS condition and then agitation was stepwise reduced at a step of 50 rpm per 6 h until it reached 400 rpm. The agitation was then maintained at this level without further change for the rest fermentation period. The oxygen supply pattern was so changed that big disturbance in fermentation and metabolism environments could be avoid, as sudden DO changes caused by rapid oxygen supply shifts are generally considered to be harmful to the physiological state of a fermentation process. With the proposed new oxygen supply strategy (NOS), the final l-arginine concentration was increased by 16% and 51%, respectively, as compared with that obtained under HOS and MOS fermentations, and the l-arginine production rate could be controlled at relatively stable and high level during the late fermentation stages. In addition, glucose consumption rate was apparently accelerated and the batch fermentation starting with the same initial glucose concentration could finish earlier when using the NOS strategy.
The metabolic flux distribution analysis indicated that, with the NOS strategy, the ATP generation rate was increased throughout the fermentation period. In addition, the two-stage oxygen supply strategy improved the l-arginine production in a way of enhancing the flux distribution ratio directed to glutamate synthesis at α-KG node in TCA cycle during late fermentation phases and maintaining the ATP generation rate throughout the fermentation at a compatible level as that of HOS condition [26,50].
Hope it was helpful