茉莉酸和双氧水对斜生褐孔菌一株黑色素缺失突变体产生酚类化合物的影响

黑色素合成是桦褐孔菌Phaeoporus obliquus次生代谢过程中的一个重要事件。黑色素的过多合成势必影响其他酚类的积累。本文以茉莉酸和双氧水为调控因子,开展了该突变体深层发酵过程酚类化合物积累研究。正常培养条件下,每升发酵液积累酚类化合物最高可达317.45mg/L,其中包括苯甲酸衍生物(45.3mg/L),黄酮苷元(74.4mg/L),黄酮苷(160mg/L)以及硬毛素类化合物(18.5mg/L)。加入茉莉酸后,总酚最大值增加到620.45mg/L,其中苯甲酸衍生物增加到230.26mg/L,黄酮苷元增加到166.86mg/L,而黄酮苷和硬毛素类化合物却分别降低到98.5mg/L和7.1mg,双氧水的加入没有提高总酚的最大积累(315.69mg/L)。因此,与野生型相比,黑色素缺失使总酚的积累有所增加,随茉莉L酸的加入总酚积累最大值增加近一倍。虽然双氧水的加入提高了苯丙氨酸裂解酶活性,但总酚的积累却没有增加,这可能是由于一部分酚类化合物在抗双氧水氧化胁迫过程中被消耗。

Effects of jasmonic acid and hydrogen peroxide on production of phenolic compounds in a melanin-deficient mutant of Phaeoporus obliquus

Melanogenesis is a key secondary metabolic process in the fungus Phaeoporus obliquus grown in natural habitats and laboratory conditions, and an overproduction of melanins reduces accumulation of other phenolic compounds. In this study, a melanin-deficient mutant of P. obliquus grown in submerged cultures was investigated for the production phenolic compounds in the presence of jasmonic acid (JA) and H2O2. The maximum level of total phenolics (MTP) produced reached 317.45mg/L. These consisted of benzoate derivatives (BD) (45.3mg/L), flavonoid aglycones (FAG) (74.4mg/L), glycosylated flavonoids (GF) (160mg/L) and hispidin analogs (HA) (18.5mg/L). With JA addition, MTP production increased to 620.45mg/L, with this increase mainly due to higher production of BD and FAG which reached 230.26mg/L and 166.86mg/L respectively. On the other hand GF and HA production fell to 98.5mg/L and 7.1mg/L, respectively. Exposure of mycelium to H2O2 reduced MTP levels to 315.69mg/L. Thus, compared to those in the wild-type, the accumulation of phenolic compounds increased after melanogenesis deletion, and was enhanced further by JA addition. Though H2O2 enhanced phenylalanine lyase (PAL) activity, MTP levels fell probably from their consumption for H2O2 detoxification.