Biotechnological Research Center Applied to the Environment (CIBAMA-BIOREN), Universidad de La Frontera, Temuco, Chile.
Chemical Engineering Department, Universidad de La Frontera, Temuco, Chile.
PLoS One. 2021 May 21;16(5):e0252113. doi: 10.1371/journal.pone.0252113. eCollection 2021.
Potato waste was processed and used as a sole substrate for simultaneously producing antifungals and biopigments using Streptomyces spp. Out of three different Streptomyces isolates, strain SO6 stood out due to its ability to produce antifungals against economically important fungal phytopathogens and intracellular biopigments using potato waste powders without additional nutrients. This strain also showed the potential to secrete a broad range of enzymes for fermentation of eight sugars that could be involved in potato waste bioconversion. The results of the fermentation assay indicated that Streptomyces sp. strain SO6 degrades potato wastes during submerged fermentation, diminishing total dry weight and increasing reducing sugars from 0.3 to 3.6 mg·mL-1 and total proteins from 70.6 to 187.7 μg·mL-1. The results showed that Streptomyces strain SO6 was able to convert the potato waste into 0.96 mg·g-1 of diffusible antifungals and 1.75 mg·g-1 of reddish-purple biopigments. On the contrary, an absence of pigment production was observed during the fermentation of the commercial medium used as reference. According to our results, replacement of commercial culture media with available low-cost agroindustrial wastes for producing bioactive chemicals is a real opportunity to enhance the Streptomyces pigment production and antibiotic sustainability with cost-competitiveness. To our knowledge, this is the first report on the simultaneous production of biopigments and diffusible antifungal antibiotics produced by Streptomyces spp. using potato solid waste as the sole nutrient source.
利用链霉菌属（Streptomyces spp.）以土豆废弃物为唯一底物同时生产抗真菌剂和生物色素。在三种不同的链霉菌分离株中，由于其能够利用土豆废弃物粉末生产抗真菌剂来对抗具有经济重要性的真菌植物病原体和细胞内生物色素，而无需额外的营养物质，因此菌株 SO6 脱颖而出。该菌株还表现出分泌广泛的酶的潜力，这些酶可用于发酵八种糖，这些糖可能参与土豆废弃物的生物转化。发酵分析的结果表明，链霉菌属（Streptomyces sp.）菌株 SO6 在液体深层发酵过程中降解土豆废弃物，减少总干重并增加还原糖从 0.3 到 3.6 mg·mL-1，总蛋白从 70.6 到 187.7 μg·mL-1。结果表明，链霉菌 SO6 菌株能够将土豆废弃物转化为 0.96 mg·g-1 的可扩散抗真菌剂和 1.75 mg·g-1 的红紫色生物色素。相反，在使用商业培养基进行发酵时未观察到色素产生。根据我们的结果，用可用的低成本农业工业废物替代商业培养基，以生产生物活性化学品，是增强链霉菌色素生产和抗生素可持续性并具有成本竞争力的真正机会。据我们所知，这是首次报道利用土豆固体废弃物作为唯一营养源，由链霉菌属（Streptomyces spp.）同时生产生物色素和可扩散抗真菌抗生素。
