Shrimali Gaurav, Shah Hardik, Thummar Kashyap, Rami Esha, Chaudhari Rajeshkumar, Schmidt Jens Ejbye, Gangawane Ajit
Department of Life Sciences, Parul Institute of Applied Science, Parul University, Vadodara 391760, Gujarat, India.
GTU-School of Applied Sciences and Technology, Gujarat Technological University, Chandkheda, Ahmedabad 382424, Gujarat, India.
Polymers (Basel). 2025 Jul 10;17(14):1904. doi: 10.3390/polym17141904.
The extensive environmental pollution caused by petroleum-based plastics highlights the urgent need for sustainable, economically viable alternatives. The practical challenge of enhancing polyhydroxybutyrate (PHB) production with cost-effective agro-industrial residues-rice-bran and corn-flour hydrolysates-has been demonstrated. GS2 was isolated from soil samples collected at the Pirana municipal landfill in Ahmedabad, India, and identified through VITEK-2 biochemical profiling and 16S rDNA sequencing (GenBank accession OQ749793). Initial screening for PHB accumulation was performed using Sudan Black B staining. Optimization via a sequential one-variable-at-a-time (OVAT) approach identified optimal cultivation conditions (36 h inoculum age, 37 °C, pH 7.0, 100 rpm agitation), resulting in a PHB yield of 2.77 g L (66% DCW). Further refinement using a central composite response surface methodology (RSM)-varying rice-bran hydrolysate, corn-flour hydrolysate, peptone concentration, and initial pH-significantly improved the PHB yield to 3.18 g L(74% DCW), representing more than a threefold enhancement over unoptimized conditions. Structural validation using Fourier Transform Infrared spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance spectroscopy (H-NMR) confirmed the molecular integrity of the produced PHB. That GS2 effectively converts low-cost agro-industrial residues into high-value bioplastics has been demonstrated, indicating substantial industrial potential. Future work will focus on bioreactor scale-up, targeted metabolic-engineering strategies, and comprehensive sustainability evaluations, including life-cycle assessment.
石油基塑料造成的广泛环境污染凸显了对可持续、经济可行替代品的迫切需求。已证明利用具有成本效益的农业工业残留物——米糠和玉米粉水解物提高聚羟基丁酸酯（PHB）产量的实际挑战。GS2是从印度艾哈迈达巴德皮拉纳市垃圾填埋场采集的土壤样本中分离出来的，并通过VITEK-2生化分析和16S rDNA测序（GenBank登录号OQ749793）进行了鉴定。使用苏丹黑B染色对PHB积累进行初步筛选。通过逐次单变量（OVAT）方法进行优化，确定了最佳培养条件（接种龄36小时、37°C、pH 7.0、搅拌速度100 rpm），PHB产量为2.77 g/L（占干重的66%）。使用中心复合响应面法（RSM）进一步优化——改变米糠水解物、玉米粉水解物、蛋白胨浓度和初始pH值——显著提高了PHB产量，达到3.18 g/L（占干重的74%），比未优化条件下提高了三倍多。使用傅里叶变换红外光谱（FTIR）和质子核磁共振光谱（H-NMR）进行结构验证，证实了所生产PHB的分子完整性。已证明GS2能有效地将低成本的农业工业残留物转化为高价值生物塑料，显示出巨大的工业潜力。未来的工作将集中在生物反应器放大、靶向代谢工程策略以及包括生命周期评估在内的全面可持续性评估上。
