Altering Nutrient Uptake and Metabolite Flow - Recombinant DNA has also been used for increasing growth rate, decreasing nutrient demand, and higher attainable cell densities in several microbes for a variety of applications. These include the following examples

(i) A glutamate debydrogenase gene, when transferred from E.coli to Methylophilus methylotrophus, increased efficiency of carbon conversion from 4% to 7% and eliminated the requirement for A TP. (M. methylotrophus has been developed as an animal feed material.)(ii) Transfer of pyruvate decarboxylase and alcohol dehydrogenase genes from Zymomonas mobilis to E. coli led to a shift from acetate production (which inhibits growth) to "ethanol production (ethanol is less inhibitory, and is an important industrial chemical). This led, to three fold increase in growth and has a potential application in conversion of several sugars found in biomass.

(v) Quantity of active protein can also be increased by genetic manipulation of protein processing pathways. Transfer of cyanobacterial rubisco genes to E. coli, and its coexpression with overexpression of E. coli genes for chaperone proteins GroES and GroEL, led to ten fold increases in the assembly of rubisco. Similar assembly of rubisco of higher plants in altered E. coli may be possible in future.