农业工程学报2016，Vol.34Issue(7)：303-308,6.DOI:10.11975/j.issn.1002-6819.2016.07.043
梨渣固态发酵培养多粘类芽孢杆菌的工艺
Cultivation ofPaenibacillus polymyxa by solid-state fermentation of pear residues
摘要
Abstract
Pear juice is one of main processed products of pear fruit in China. A lot of pear residues are produced during pear juice processing, and the waste is up to 40%-50% of pear fruit weight. Because pear residues contain manystone cells and can not be used directly as animal feed, most of them have to be discarded in fields or near factories.Paenibacillus polymyxa is a widely distributed bacterial species in the environment, and has no pathogen to humans, animals and plants.P.polymyxa strain produces several antibiotics and hydrolytic enzymes, which play an important role in the biocontrol of plant pathogens and the promotion of plant growth. It is reported to be both a plant-growth-promoting and effective biocontrol agent.P. polymyxaD1, a naturally occurring biocontrol agent isolated from soil, can stimulate plant growth and effectively suppresse several soil-borne diseases. Many researches on submerged fermentations ofP. polymyxa have been done, but study on its solid-state fermentation has not been reported at the present. In this work, fresh Yali pear’s residues were used to cultivateP. polymyxa D1 in a solid-state fermentaion. Fresh Yali pear’s residues contained 76.2% moisture, 5.5% residual sugars and 0.32% proteins. The effects of cultivation conditions on its cell growth and sporulation were investigated. The results showed that pear residues were good material for solid-state fermentation and very suitable to cultivate P. polymyxaD1. The mositure of fresh Yali pear’s residues was very high, which might not be in favour of the cell growth during solid-state fermentation. Addition of wheat bran into pear residues improved significantly the cell growth. The possible reason of this result was that oxygen supply and nutritional status of the culture medium were improved obviously when pear residues were mixed with wheat bran. When the ratio between pear residue and wheat bran was 5:2, the highest viable cell number was achieved, 2.5×109cfu/g. Spore number was an important parameter of microbial agent. Cultivation conditions could influence bacterial sporulation. The viable cell number and spore yield ofP. polymyxaD1 obviously increased when urea, sodium nitrate and soybean meal were added into the cultural medium of pear residues, and soybean meal had the best stimulation effect. However, NH4NO3, NH4Cl and degossypolized cottonseed protein inhibited the cell growth and spore formation. Mineral salts also influenced the cell growth and sporulation ofP. polymyxaD1. Supplement of NaCl, MgSO4, CaCO3 and FeSO4 into the medium largely inhibited the spore formation ofP. polymyxaD1. Addition of KH2PO4 greatly promoted the cell growth and sporulation, and its spore yield and sporulation efficiency were 4.52×109 cfu/g and 95.6%, respectively.P. polymyxa is a highly anaerobic bacterium. The spore yield of P. polymyxaD1 decreased obviously as the medium volume in the fermenter increased. The optimal cultivation temperature ofP. polymyxaD1 was 34°C, which was higher than that in submerged frementation. The optimal cultivation time ofP. polymyxaD1 was 120 h. It was found that the spores were formed very slowly by the cells of P. polymyxaD1 when cultivated with pear residues in solid-state fermentaion, compared with submerged fermentation.关键词
发酵/工艺/细菌/梨渣/多粘类芽孢杆菌/芽孢Key words
fermentation/technology/bacteria/pear residue/Paenibacillus polymyxa/spore分类
农业科技引用本文复制引用
赵国群,牛梦天,卢士康,关军锋..梨渣固态发酵培养多粘类芽孢杆菌的工艺[J].农业工程学报,2016,34(7):303-308,6.基金项目
国家现代农业[梨]产业技术体系建设专项（cars-29）；河北省科技计划项目（14222902D）。 （）
