passages.id: split_5_test_3423_passage
passages.type: progene_text
passages.text: L-Ornithine production increased from 0.3 to 3.2 mg / g ( dry cell weight ) when the primary L-ornithine biosynthetic pathway was optimized by disrupting the pathway transcription repressor , thereby increasing the expression of the genes involved in the pathway , and by preventing conversion of L-ornithine into citrulline .