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Two new sarsolenane diterpenes, dihydrosarsolenone (2), methyl dihydrosarsolenoneate (3), and two new capnosane diterpenes, sarsolilides B (5) and C (6), were isolated together with the known analogue, sarsolilide A (4), from the Hainan soft coral Sarcophyton trocheliophorum Marenzeller. Their structures were elucidated by detailed spectroscopic analysis and by comparison with reported data, leading to a structure revision of sarsolenone (1). The absolute configurations of 2[a] State Key

Marine-polysaccharide degrading enzymes have recently been studied extensively. They are particularly interesting as they catalyze the cleavage of glycosidic bonds in polysaccharide macromolecules and produce oligosaccharides with low degrees of polymerization. Numerous findings have demonstrated that marine polysaccharides and their biotransformed products possess beneficial properties including antitumor, antiviral, anticoagulant, and anti-inflammatory activities, and they have great value in healthcare, cosmetics, the food industry, and agriculture. Exploitation of enzymes that can degrade marine polysaccharides is in the ascendant, and is important for high-value use of marine biomass resources. In this review, we describe research and prospects regarding the classification, biochemical properties, and catalytic mechanisms of the main types of marine-polysaccharide degrading enzymes, focusing on chitinase, chitosanase, alginate lyase, agarase, and carrageenase, and their product oligosaccharides. The state-of-the-art discussion of marine-polysaccharide degrading enzymes and their properties offers information that might enable more efficient production of marine oligosaccharides. We also highlight current problems in the field of marine-polysaccharide degrading enzymes and trends in their development. Understanding the properties, catalytic mechanisms, and modification of known enzymes will aid the identification of novel enzymes to degrade marine polysaccharides and facilitation of their use in various biotechnological processes. K E Y W O R D S agarase, alginate lyase, carrageenase, chitinase, chitosanase 1 INTRODUCTION Ocean occupies >70% of the global surface, and the vast oceanic water environment has spawned large and complex marine ecosystems with rich biodiversity. There is a wide variety of marine resources, however, they are largely unexploited. This situation makes the marine environment very attractive for bioprospecting to discover new functions and molecules (Arnaud-Haond, Arrieta, & Duarte, 2011). Research into marine compounds, especially polysaccharides from renewable biomass, is attracting increasing attention. Polysaccharides make up one of the largest