Spot marine biofuel premiums have weakened further at the world's largest bunker hub Singapore, weighed by slow demand, market sources said this week.Premiums for the flagship B24 marine biofuel blend recently traded between $120 to $130 a metric ton over 0.5% low sulphur fuel oil quotes…<p><p>https://www.marinelink.com/news/singapore-marine-biofuel-premiums-drop-512908</p></p>