Polyhydroxybutyrates (PHBs), biodegradable plastics, having properties similar to conventional plastics, exhibit a high potential for replacing petrochemical-based non-degradable plastics. But a major obstacle in their large-scale commercial production is high production cost, one of the key factors responsible for which is the expensive carbon sources that are currently being used in their manufacturing process. The present work was aimed to study PHB production using cost-effective substrates as carbon sources in the production medium. Inexpensive agro-industrial byproducts (molasses, cheese whey, wheat bran and banana peel, used in different concentrations) were explored for their potential to substitute the conventional costly substrates. Compared to glucose, all the four alternate carbon sources showed an enhancement in PHB production. The mean percent increase in PHB production was in the range of 3.81% to 7.23%. However, some of the bacterial isolates showed an enhancement as high as 23.32% and 19.65%. Highest mean PHB yield was observed in molasses (135.18 mg/mL), followed by cheese-whey (133.79 mg/mL), banana peel, and least in wheat bran based production medium. On dry weight basis, PHB accumulation in cells was observed to be 64.32% and 64.29% of the total dry cell weight with molasses and cheese whey, respectively, as carbon sources. FTIR spectra of extracted PHB were found to be comparable to the spectra of standard PHB, thus, confirming the chemical nature of the extracted polymer.

中文翻译：

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农产品工业副产品，作为生产聚羟基丁酸酯的另一种经济高效的培养基成分

具有类似于常规塑料的性能的可生物降解的塑料聚羟基丁酸酯（PHB）具有很高的替代石油化学基不可降解塑料的潜力。但是，大规模商业化生产的主要障碍是生产成本高昂，其主要原因之一是目前在其制造过程中使用的昂贵碳源。目前的工作旨在研究使用经济高效的底物作为生产介质中的碳源的PHB生产。探索了廉价的农工副产品（糖蜜，奶酪乳清，麦麸和香蕉皮，以不同的浓度使用）具有替代常规昂贵底物的潜力。与葡萄糖相比，所有四个替代碳源均显示出PHB产量的增加。PHB生产的平均百分比增长在3.81％至7.23％的范围内。然而，一些细菌分离株显示出高达23.32％和19.65％的增强。在糖蜜中观察到最高的PHB平均产量（135.18 mg / mL），其后是干酪乳清（133.79 mg / mL），香蕉皮，而在以麦麸为基础的生产培养基中观察到的最低。以干重为基础，观察到PHB在细胞中的积累分别占糖蜜和干酪乳清作为碳源的干细胞总重的64.32％和64.29％。发现萃取的PHB的FTIR光谱与标准PHB的光谱相当，从而证实了萃取的聚合物的化学性质。在糖蜜中观察到最高的PHB平均产量（135.18 mg / mL），其后是干酪乳清（133.79 mg / mL），香蕉皮，而在以麦麸为基础的生产培养基中观察到的最低。以干重计，以糖蜜和干酪乳清为碳源，PHB在细胞中的积累分别占干细胞总重的64.32％和64.29％。发现萃取的PHB的FTIR光谱与标准PHB的光谱相当，从而证实了萃取的聚合物的化学性质。在糖蜜（135.18 mg / mL）中观察到最高的平均PHB产量，其次是干酪乳清（133.79 mg / mL），香蕉皮，在以麦麸为基础的生产培养基中最低。以干重为基础，以糖蜜和干酪乳清为碳源，观察到PHB在细胞中的累积分别占干细胞总重的64.32％和64.29％。发现萃取的PHB的FTIR光谱与标准PHB的光谱相当，从而证实了萃取的聚合物的化学性质。