搅拌转速和通气量对灰树花多糖组成及相关酶活性的影响

考察了搅拌转速和通气量对灰树花(Grifola frondosa)菌丝体多糖和胞外多糖提取物中的单糖组成及糖合成相关酶活性的影响.结果表明:搅拌转速和通气量对灰树花胞外多糖提取物的单糖组成影响不大,其葡萄糖比例维持在95%以上;而对菌丝体多糖提取物的单糖组成及相关酶活力影响显著.4个搅拌转速梯度中,以60 r/min时,菌丝体多糖提取物中的甘露糖比例最大,为51.1%,GDP-甘露糖焦磷酸化酶(GMPPB)比酶活最高,为82 mU/mg;4个通气量梯度中,当通气量为0.50 vvm时,甘露糖比例最大(35.7%),磷酸葡萄糖异构酶(PGI)与GMPPB比酶活分别达到最高值,为547 mU/mg和67 mU/mg.

Effect of Agitation and Aeration on theMonosaccharide Components of Grifola frondosaPolysaccharides and on Enzymes Associated withPolysaccharide Biosynthesis

Monosaccharide composition of G.frondosa exo-polysaccharide (in which the glucose content >95%) was only marginally affected when the fungus was grown in submerged culture under different agitation and aeration regimes.Conversely, the glucose component of mycelium-associated polysaccharide (MAP) ranged between 45.1%-66.5% and 55.7%-73.7% in cultures subjected to variable agitation (60-250 r/min) and aeration (0.25-1.0 vvm) regimes, respectively.Highest amounts of mannose (51.1%) and mannose (35.7%) in MAP were recorded at an agitation rate of 60 r/min and an aeration rate of 0.50 vvm, respectively.An agitation rate of 60 r/min also resulted in the highest recorded GDP-mannose pyrophosphorylase (GMPPB) activity (82 mU/mg protein), whereas highest PGI and GMPPB activities (547 mU/mg protein and 67 mU/mg protein, respectively) were registered when the aeration rate was set at 0.5 vvm.