Citigroup revises earnings estimates of Global Bio-chem Technology Group (0809.HK) to incorporate lower-than-expected lysine margin in 1H07, exceptional gain, minorities from sweetener spin-off. Adds "operating environment is improving - product prices firm and corn cost falling. Balance sheet has also strengthened after the spin-off." Keeps on Buy, HK$4.03 target price. Says capex will likely fall to HK$500 million in FY08 from HK$1.3 billion in FY06. Stock flat at HK$2.98.